Eating, Aging, and the Brain

Two recent studies shed new light on the relationship between food and the brain.

The first study involves mice on a calorie-restricted diet. Restricting calories to about 70% of normal intake kept the mice—and their rodent brains—young when compared to control mice who could eat whenever they wanted. And while there’s no proof yet that this works with human beings, there is a lot of interest by researchers in finding out what is going on in the relationship between aging and eating.

The latest research is reported in the December 19 of PNAS. Researchers at the Catholic University of Sacred Heart in Rome report their finding that a naturally-occurring protein, CREB1, plays a key role in mediating between caloric restriction and the delay of aging. Caloric restriction seems to trigger CREB1, which in turn activates many other genes involved in longevity and brain function.

What is new in this research is the relationship between caloric restriction and CREB1 activity. Discovering how these molecules interact opens the possibility that the activity of CREB1 can be increased without having to keep to a fairly austere diet.

According to Giovambattista Pani, one of the lead researchers, “Our hope is to find a way to activate CREB1, for example through new drugs, so to keep the brain young without the need of a strict diet.”

“This discovery has important implications to develop future therapies to keep our brain young and prevent brain degeneration and the aging process. In addition, our study shed light on the correlation among metabolic diseases as diabetes and obesity and the decline in cognitive activities,” according to Dr. Pani.

The second study is published in the December 28 issue of Neurology and does involve human beings. Just in time for New Year’s resolutions, researchers at Oregon State University report on the brains and the diets of 104 seniors with an average age of 87. The result is pretty sobering. Those who ate fast foods and snack loaded with trans-fats scored much worse on cognitive tests than those who ate diets rich in the healthy oils commonly found in fish or consumed high levels of vitamins B, C, D, and E.

How much worse? The fast-food seniors scored 17% lower on thinking and memory tests and had a shocking 37% lower active brain size based on an MRI. And that’s after other factors such as age or education level are removed. Diet alone, it appears, makes a significant difference. Eating the right food seems to help slow down the age-related shrinkage of the brain.

Someday there might be a pill that makes us and our brains resist aging. For now, it’s what we eat that counts. These results need to be confirmed, but obviously it is very exciting to think that people could potentially stop their brains from shrinking and keep them sharp by adjusting their diet," according to Gene Bowman of the Oregon Health & Science University in Portland and author of the study.

This would not have surprised Saint Athanasius, bishop of Alexandria in the mid-4th century. Like many of his age, Athanasius was fascinated by the story of Saint Anthony of Egypt, one of the earliest Christian ascetics. Athanasius wrote a spiritual biography of Anthony, interpreting his life and turning him into the prototype of Christian monks.

Anthony gave away the family fortune and lived in isolation in the Egyptian desert, eating almost nothing. The result? He lived to 105 and was known for his wisdom to the very end.

Todd Daly has written about Athanasius and Anthony, including an essay in my recent book, Transhumanism and Transcendence. Daly makes it clear that Anthony’s purpose was not longevity or a youthful brain. This is no science experiment, and if Anthony is the first monk, he’s not the first transhumanist. But according to Athanasius (and to Daly), Anthony is conducting a spiritual experiment. His question is whether it is possible to regain some small portion of the original human condition…humanity as God intended, in other words, rather than the fallen humanity we experience. By denying his body, he sought to expand his soul. Without realizing it, he kept his brain from shrinking.

The amazing thing is that by asking a seemingly arcane theological question—and by sticking with it for decades—Anthony anticipates today’s research.

The PNAS article was published on December 19. The Oregon study was published online on December 28 by the journal Neurology.

Are You as Empathetic as a Rat?

Empathy is the capacity to share the emotional state of another. Politicians claim to have it when they say “I feel your pain.”

Even if they do not always show it, human beings are clearly capable of empathy. Other primates such as chimps have been observed acting in a way that is best explained by empathy. Rather than acting for their own benefit, they sometimes act because they share the feeling or distress of another chimp. Such behavior is said to be “empathy-driven.”

Once it was thought that only human beings could feel empathy. Now researchers are finding that empathy-driven behavior is more widespread than previously imagined. Not just other primates but even rodents, it seems, are biologically capable of empathy. For all the differences between the human and the rat brain, we share fundamental circuits that make it possible to feel the emotions of another, particularly when the other is in pain or distress.

In a simple experiment reported in the December 9 issue of the journal Science, researchers provide solid evidence that the much-maligned rat is capable of acting in a way that is most easily explained by empathy.

"This is the first evidence of helping behavior triggered by empathy in rats," said Jean Decety, a member of the research team at the University of Chicago. "There are a lot of ideas in the literature showing that empathy is not unique to humans, and it has been well demonstrated in apes, but in rodents it was not very clear. We put together in one series of experiments evidence of helping behavior based on empathy in rodents, and that's really the first time it's been seen," Decety said in a release issued by the University.

In order to act in a way that is empathy-driven, an animal must be capable of “emotional contagion.” To test whether rats have this capacity, an experiment was designed Chicago psychology graduate student Inbal Ben-Ami Bartal. Two rats were placed in an enclosure, one of them roaming freely while the other was locked inside a tube. The free rat, in time, could discover how to open the lock, but there was no reward for doing so.

The experiment was designed observe whether rats show they are capable of emotional contagion. Was the free rat biologically capable of emotional concern or what the paper defines as “an other-oriented emotional response elicited by and congruent with the perceived welfare of an individual in distress”?

PHOTO: ©Science/AAAS.

The free rats not only learned to open the container but did so repeatedly when it held another rat, something they did not do if it was empty or if it contained a stuffed animal.

Even more striking was their behavior when chocolate chips were involved. In one variation on the experiment, two enclosures were used, one with an enclosed rat and the other with five pieces of chocolate. The free rat has a choice: free the cagemate or eat the chocolate first. In the absence of empathy, the free rat will make the selfish choice. But at least half the time, the rat freed its cagemate first. According to the report, “these results show that the value of freeing a trapped cagemate is on par with that of accessing chocolate chips.”

"On its face, this is more than empathy, this is pro-social behavior," said Jeffrey Mogil of McGill University, who was not involved in the study. "It's more than has been shown before by a long shot.”

Without claiming to know what rats think, the authors conclude their report with their opinion that “the free rat was not simply empathetically sensitive to another rat’s distress but acted intentionally to liberate a trapped” member of their own species.

If rats are indeed capable of empathetic feelings, then it becomes clear that the biological substrate for shared emotion is deep in our evolutionary past and deep in the earlier parts of our brains. Far from being uniquely human, empathy seems to be widely shared. What is uniquely human, perhaps, is the way we override it with self-interest.

As I prepared this post, I was interrupted several times by others who were speaking of the history of racism in America and particularly the history of slavery. When I saw the pictures of rats in their enclosure, my mind went to chains and slave ships. If empathy is so deep in our mammalian evolution, so deeply rooted in our brains, what extraordinary rationalizations do we conjure up to negate it?

The paper, "Empathy and Pro-Social Behavior in Rats," is published Dec. 9 by the journal Science. http://www.sciencemag.org/content/334/6061/1427.abstract

Enhancing the Brain: A New Approach?

A molecule that protects you against viruses may also be slowing down your brain. That’s the startling finding just reported by researchers at the Baylor College of Medicine.

In the December 9 issue of Cell, a research team led by Mauro Costa-Mattioli report on how a key component of the immune system may also play a central role in the brain’s ability to form memories.

The molecule in question is the enzyme “protein kinase RNA-activated” or PKR for short. PKR is well-known to biomedical researchers. It is found in nearly all vertebrates and helps fight viral infections.

What was unknown is how PKR plays a pivotal role in regulating how the brain forms memories. Using mice, Costa-Mattioli’s team found that PKR actually slows down the brain’s ability to form memories. By blocking the production of PKR in mice, Costa-Mattioli’s team was able to produce mice with enhanced memory.

“The molecule PKR (the double-stranded RNA-activated protein kinase) was originally described as a sensor of viral infections, but its function in the brain was totally unknown," said Costa-Mattioli in a press release issued by Baylor Medical College.

The researchers used two methods to block PKR. They produced mice that were genetically modified so they couldn’t produce PKR. But they also used a drug that inhibits the production of PKR. In both cases, memory capacity was enhanced.

How does PKR act in the brain? Apparently by interacting with another key molecule, interferon-γ or IFN-γ, which is also best known for its role in the immune system. Researchers believe that in the brain, PKR and IFN-γ interact, keeping each other in balance. Suppressing PKR seems to increase the role of IFN-γ and the activity of the brain, particularly the neurons that are creating long-term memories.

“These data are totally unexpected, and show that two molecules classically known to play a role in viral infection and the immune response regulate the kind of brain activity that leads to the formation of long-term memory in the adult brain,” said Costa-Mattioli.

What is perhaps most startling about the report is that a drug that inhibits PKR enhances memory in mice. “It is indeed quite amazing that we can also enhance both memory and brain activity with a drug that specifically targets PKR,” according to Costa-Mattioli.

If a drug enhances memory capacity in mice, could it work in humans? That’s a big jump, one that will take much more research before anything is even tested in human beings. But researchers suggest that this is possible and worth exploring. Costa-Mattioli said, "More investigation is undoubtedly necessary to translate these findings to effective therapies but we would be delighted if our scientific studies were to contribute in some way to this ultimate goal."

“Our identity and uniqueness is made up of our memories," Costa-Mattioli said. "This molecule could hold the key to how we can keep our memories longer, but also how we create new ones.”

Will this provide a new strategy in dealing with diseases that rob us of our old memories and of our capacity to create new ones? Given the stakes, research will explore these possibilities.

If the research is applicable to human beings (and why not?) and if it provides a new path to preventing or delaying dementia, it will also open new ways to think about the enhancement of human cognition. The mice in the study were not suffering from any memory loss, but the speed at which they were able to learn a new task was enhanced nearly four-fold.

Given the wide-spread interest in cognitive enhancement, especially on university campuses and among transhumanists, we should expect to hear more about how inhibiting PKR just may make you smarter.

The article, "Suppression of PKR Promotes Network Excitability and Enhanced Cognition by Interferon-γ-Mediated Disinhibition,” appears in the December 9 issue of Cell.

Evolutionary Fast-Track for Human Brains

More than 35 years ago, Allan Wilson and Mary-Claire King made an astonishing proposal. Maybe what separates humans and chimps is not just our genes. Maybe it’s also how our genes are expressed or regulated.

Research published in today’s issue of PLoS Biology builds on decades of intervening advances in evolution and genetics and take the question much further. The difference between humans and nonhuman primates in cognitive ability is explained in large part by differences in gene expression, especially during the critical periods when young brains are being formed.

Humans share many of their genes with other species, especially chimps. In fact, we share so many genes that it is hard to explain how we can be so different in terms of cognitive ability. If genes make all the difference, how can they explain the differences between chimp and human brains? And how can a mere six million years of human-chimp divergence give us enough time to accumulate enough genetic change?

The answer seems to lie in the relatively rapid evolution of differences in gene expression. In other words, while the genes themselves evolved slowly, the regulation of their expression evolved more rapidly. It’s not just the genes but their expression that’s important. It’s not just the evolution of genes but the evolution of gene expression that drives the rapid divergence between human and chimp brains.

This is especially true in the genes that control the development of the prefrontal cortex of the brain. In other words, there has been relatively rapid evolution in the genetic mechanisms that regulate genes directly responsible for the early-childhood neural development of the critically-important prefrontal cortex, which is involved in abstract thinking, planning, social intelligence, and working memory.

According to the article, “humans display a 3-5 times faster evolutionary rate in divergence in developmental patterns, compared to chimpanzees.” Most important, however, is the way this research identifies specific regulators that have evolved rapidly since human-chimp divergence. These regulators are “micro-RNAs,” some of which are specifically identified in the article, with the claim that “changes in the expression of a few key regulators may have been a major driving force behind rapid evolution of the human brain.”

According to the study’s senior author, Philipp Khaitovich, this finding suggests that "identifying the exact genetic changes that made us think and act like humans might be easier than we previously imagined." Kkaitovich was quoted in a press release issued by the journal, PLoS Biology.

The article is entitled "Micro-RNA-Driven Developmental Remodeling in the Brain Distinguishes Humans from Other Primates" and appears in the December 6 issue of PLoS Biology, where it is freely available to the public.

Violence and Children's Brains

When children are exposed to violence in the family, their brains are visibly changed. That’s the disturbing message of new research published in tomorrow’s issue of Current Biology.

According to the research article, exposure to violence at home can “represent a form of environmental stress that significantly increases [the] risk of later psychopathology, including anxiety.” It’s as if violence tunes the child’s brain to expect more violence.

Earlier studies have shown that physically abused children show “selective hypervigilance to angry cues,” such as pictures of angry faces. Another earlier study used functional magnetic resonance imaging (fMRI) to show increased brain reactivity. When individuals with anxiety disorder where shown angry faces, two brain regions were overly reactive: the anterior insula (AI) and the amygdala. The same response was found in soldiers exposed to combat.

The new research takes this a step further. Children exposed to family violence, including violence between parents, also showed the same increased brain reactivity. The reaction was quite specific in that they responded to pictures of angry faces, not sad faces.

Most important, perhaps, is that this study looked at brain function rather than symptoms of anxiety or depression. In terms of behavior, the children seemed quite normal. Their brains, however, tell a different story, one of being tuned to be anxious.

Some might suggest that given all the violence in the world, the reaction is beneficial. Maybe it’s a good thing that some human beings learn to be especially responsive to potential threats.

But as the researchers note, excessive reactivity “may also constitute a latent neurobiological risk factor increasing vulnerability to psychopathology.” The researchers also found that the degree of the brain reactivity depended on the severity of the violence.

The research “underlines the importance of taking seriously the impact for a child of living in a family characterized by violence. Even if such a child is not showing overt signs of anxiety or depression, these experiences still appear to have a measurable effect at the neural level,” said Eamon McCrory of University College London, lead author, in a press release from the journal.

More than that, this research shows how violence and trauma affect human beings in ways that permanently alter the brain.

The article, “Heightened Neural Reactivity to Threat in Child Victims of Family Violence,” appears in the December 6 issue of Current Biology.

For previous work by some of these same researchers, see “The Impact of Childhood Maltreatment: A Review of Neurobiological and Genetic Factors,” published in July in Frontiers in Psychiatry.

Searching for Life on Other Planets

This post is a little bit out of my usual orbit. Literally. It has to do with newly discovered planets that orbit other suns. They’re called “extra-solar planets” or simply “exoplanets.”

Over the past twenty years, scientists have discovered nearly 700 such planets. Most of these are too big and too hot for life. Their powerful gravity and their vaporizing heat make it unlikely that any form of life could arise, much less evolve.

PHOTO CAPTION: Scientists are now starting to identify potential habitable exoplanets after nearly twenty years of the detection of the first planets around other stars. This image shows all known examples using 18 mass and temperature categories similar to a periodic table, including confirmed and unconfirmed exoplanets. Only 16 in the Terrans groups are potential habitable candidates. PHOTO CREDIT: PHL copyright UPR Arecibo

A few exoplanets may have the right conditions for life. So far, at least two exoplanets seem to have roughly “earth-like” conditions, making them what researchers call “habitable exoplanets.”

More will surely be discovered. So many more, in fact, that some sort of catalog is needed. Enter the “Habitable Exoplanets Catalog,” hosted at the University of Puerto Rico. The Catalog is being introduced on December 5, 2011 to astronomers at the Kepler Science Conference in California.

The Catalog is an online database of habitable worlds. There’s no proof yet that life exists on any of them, but many researchers believe that some forms of life will be discovered once our detection technology advances just a bit further, with probes such as NASA’s Kepler.

”New observations with ground and orbital observatories will discover thousands of exoplanets in the coming years. We expect that the analyses contained in our catalog will help to identify, organize, and compare the life potential of these discoveries,” said Abel Méndez, Director of the PHL and principal investigator of the project in a press release issued by the University of Puerto Rico.

One nice feature of the Catalog is its “periodic table of exoplanets.” Everyone remembers the periodic table of elements that hangs in every science classroom. Just as that table organizes elements by their properties, so the table of exoplanets organizes them by habitability. What’s more, because it is an online database, new discoveries are included and organized as they occur.

To achieve this, the Catalog uses data from other databases, such as the Extrasolar Planets Encyclopedia,Exoplanet Data Explorer, the NASA Kepler Mission, and other sources.

The Secret Lives of Cells Revealed

Life at the cellular level is chaotic and complex, beautiful and yet deadly.

Even though we are made up of trillions of cells, most of us give our individual cells about as much thought as a piece of sandstone thinks about individual grains of sand.

Enter the new technologies of imaging, which open new worlds. As never before, we can see the very small and the very distant.

On December 3, the American Society for Cell Biology announced the winners of the Celldance 2011 Film and Image Contest Winners.

Take a look. Unless you’re a cell biologist, it will change the way you see the world. It will re-define your relationship to your own body. It will open new vistas on the much quoted “fearfully and wonderfully made.” If only the psalmist could have seen this!

My favorite is the first place winner, “Cancer Dance.” I say “favorite” with a great deal of qualification. It’s hard to look at this film. If you know someone who has faced cancer—and who doesn’t—what you see in this film will shock and anger you. And then you have to think: cancer is happening inside all of us pretty much all the time. Fortunately, it doesn’t get the upper hand…unless it does.

When I teach the introduction to theology, I talk about God, creation, pain in nature, and human suffering at the hands of nature. Cancer is the main example. Describing this disease theologically is a real challenge. Quite simply, cancer uses the mechanisms of life to destroy lives. It turns everything good bad.

I once asked an oncologist friend who is a Christian: “When you look at a cancer cell, theologically, what do you see?” He was so astounded by the question that he couldn’t answer.

Now, thanks to this video, you can ask yourself that question. Theologically, what is going on here? What the bleep is going on here? Why would God design such a system?

So from now on, when I teach theology, I’ll run the video. I won’t have answers. I will hope my students will learn that their standard answers might not be so useful after all.

Finally let me add that I am looking forward to the publication of a book called Chance, Necessity, Love: An Evolutionary Theology of Cancer. It’s the work of Leonard M. Hummel, who teaches Pastoral Theology and Care at the Lutheran Theological Seminary at Gettysburg, and Steve James, Associate Professor of Molecular Biology at Gettysburg College. I’ll update when the book is available.

Here again is the LINK to the videos. Each one is a winner. We nonscientists owe a great debt to the hardworking young researchers who spent hours showing us what we’re made of. For a theologian, it's a revelation.

Cognitive Enhancement: Campus Update

Use of drugs to boost academic performance is nothing new, but The Washington Post has just published a news story suggesting that use of these drugs is increasing on college campuses.

The story, written by Post reporter Jenna Johnson, refers to a study at the University of Maryland that suggests that students who take cognitive enhancers study less, party more, and have slightly lower grade point averages than their classmates. That suggests that their main purpose for using the drugs is stay competitive without letting studies get in the way of college.

There is little doubt, however, that the drugs are also being used by highly focused, academically competitive students in demanding programs. Their purpose: to add an edge to their hard work in order to stay in the top one or two percent of the competitive pile. As the Post reports, one name for these drugs is “Ivy League crack.”

The drugs in question are familiar enough—mostly Ritalin and Adderall. Students without prescriptions can easily buy these drugs from other students.

Should use of these drugs be treated as crimes? Or should those who wish to excel academically be allowed to use whatever means helps them achieve that end? For more on that debate, see the now-classic 2008 article in the journal Nature, in which prominent bioethicists such as Stanford’s Henry Greely argue for greater tolerance and openness.

Science and Technology in Theological Perspective

Most of the time, my posts address the latest developments in key areas of science and technology.

Occasionally, it’s helpful to stand back and ask whether it is possible to put these developments together into a broader picture. The speed of scientific discovery can make our heads spin. Can we put things together? Is it possible to offer a theologically coherent view of science and technology today?

One of the boldest attempts along this line is the “Pastoral Letter” released by the United Church of Christ early in 2008. The full title of the Letter is "A New Voice Arising: A Pastoral Letter on Faith Engaging Science and Technology."

When the Letter first appeared, one person to recommend it was Alan Leshner, Executive at the American Association for the Advancement of Science. He wrote:

I am delighted to see the United Church of Christ's clear support of science. I believe that science and religion are complementary to each other, and should not be seen as competing ways of looking at the world; they are concerned with different questions. In an era of such rapid science and technology advances – advances that bring benefits as well as, at times, risks -- and when science and technology are becoming ever-more imbedded in every aspect of modern life, it is essential that we maintain an active dialogue among scientists, ethicists, and religious communities. In the same way that UCC states that it cannot ignore the context in which it functions, neither can the scientific community ignore its societal context. For this reason, we see a dialogue between science and religion as vital.

While science and technology have continued to advance rapidly since 2008, the themes expressed in the Letter remain current. Church groups have used it as a study document. Clergy have used it for sermons. My guess is that they will continue to do so.

The Great Migration: Tools Mark the Trail

Anatomically modern humans (AMH)—people who looked pretty much like us—migrated out of Africa tens of thousands of years ago and settled across Asia and Europe.

Just who were these people, how long ago did they migrate, and what route did they first take? These are some of the biggest questions in archeology. Now at last researchers seem to be closing in on concrete answers.

In a report published in the November 30 issue of the open-access journal PLoS ONE, an international research team led by Jeffrey Rose presents its analysis of recent work in southern Oman, located on the southeastern corner of the Arabian peninsula.

For years, researchers have debated with each other over the earliest migration route. Was it across the Red Sea to the Arabian boot heel (sea levels being much lower then)? Or was it north from Egypt along the Mediterranean?

Rose and his team found evidence suggesting that AMH residents of the Nile valley migrated—with their distinctive tool technology—to present day Oman. Their analysis of over 100 sites in Oman led researchers to believe that the tool culture was clearly the same in both settings. In other words, one culture spans two continents, clearly supporting the idea of human migration.

Scientists have long known about the Nile valley culture, which they call “Nubian.” The breakthrough reported here is the strong evidence that Nubian toolmakers made their way out of Africa to Arabia, bringing their characteristic stonecutting techniques with them.

The date of migration, according to the report, is at least 106,000 years ago, perhaps earlier.

No human remains were found with the stone tools. This leaves open the possibility that some other humans—“archaic” and not anatomically modern—may be responsible for the stone tools. The researchers dismiss this idea on the grounds that AMH seem to be the only form of humans present in North Africa at the time of the migration.

“After a decade of searching in southern Arabia for some clue that might help us understand early human expansion, at long last we've found the smoking gun of their exit from Africa,” according to Rose, a Research Fellow at the University of Birmingham.

Another surprise contained in the report is that the stone tools were found inland rather than right along the coast. “For a while,” remarks Rose, “South Arabia became a verdant paradise rich in resources – large game, plentiful freshwater, and high-quality flint with which to make stone tools,” according to a press release issued by PLoS One. One possibility is that the “southern route” out of Africa along the southern Arabian peninsula was not so much a coastal expressway to Asia and Europe as it was a settling of the interior of Arabia.

The report, “The Nubian Complex of Dhofar, Oman: An African Middle Stone Age Industry in Southern Arabia,” appears in the November 30, 2011 issue of PLoS ONE

Seminaries and Science

How can seminaries do a better job in helping future clergy become more aware of developments in science and technology?

That was the focus of a panel last week at the American Academy of Religion Meeting in San Francisco. Lead-off speakers were Dan Aleshire, Director of the Association of Theological Schools and Jennifer Wiseman, who directs the program of Dialogue on Science, Ethics and Religion at the American Association for the Advancement of Science.

Then it was my turn. I pointed out the obvious. There’s no room in the theological curriculum to add anything. Faculty wouldn’t know what to add if they had the time. Students would be able integrate it into what they are already learning. So why bother?

I suggested that seminaries need to remember that their job is to teach theology. Doing our job well today, I argued, means that we have to take science and technology into account. One reason why this is so is because theological ideas or doctrines come mixed with outdated philosophical notions of nature.

For Christianity, this is a real challenge. Our core idea—redemption—is built on a myth of an original human nature that is lost and then restored. Unless students are minimally aware of how science challenges this thinking, seminaries aren’t doing their job.

I also suggested that for today’s students, my classroom references to current science almost always brought the subject matter to life. Students today are not so familiar with philosophy or other sources of criticism of theology. They have an easier time understanding how science challenges traditional ideas and forces them to think. They welcome the challenge. After all, they like to think that their education is relevant to the world in which they will serve.

Seminaries today need to focus on the basics—like theology—and teach it the right way right from the beginning, starting with introductory courses.

Sure, advanced electives are fine. I teach them myself, everything from “Christianity and Evolution” to “Ethics and the Technologies of Human Enhancement.” But the real key for seminaries, I believe, is to teach the core of the curriculum in a way that is appropriate for the clergy of today.

Here's where you'll find more about the AAAS program on seminary education, including recent news about an earlier program.

Brain Regeneration: Mouse Brains and Human Futures

Embryonic stem cells are surprisingly capable of regenerating portions of the brains of mice according to a report published in the November 25 issue of the journal Science. What is unexpected about this report is not the extent of the repairs so much as where they occurred in the brain.

The hypothalamus, which is involved basic metabolism and complex behaviors, has usually been regarded as less open to regeneration, whether naturally or by biomedical intervention. Naturally, a limited number of neurons develop during adulthood, but these are not enough to restore this area of the brain after injury or disease. “The neurons that are added during adulthood in both regions are generally smallish and are thought to act a bit like volume controls over specific signaling,” explained Jeffrey Macklis of Harvard Medical School and one of the lead researchers in the study.

“Here we've rewired a high-level system of brain circuitry that does not naturally experience neurogenesis,” Macklis said, “and this restored substantially normal function.”

The report reached this conclusion: “these experiments demonstrate that synaptic integration… [by] donor neurons can impart an organism-level rescue of metabolic defects, thereby providing a proof of concept for cell-mediated repair of a neuronal circuit controlling a complex phenotype.”

While it is important to underscore that this work is performed on mice, the results suggest that something similar might be possible someday in human beings with brain injuries. “The finding that these embryonic cells are so efficient at integrating with the native neuronal circuitry makes us quite excited about the possibility of applying similar techniques to other neurological and psychiatric diseases of particular interest to our laboratory," according to Matthew Anderson in a press release issued by Harvard Medical School.

For now, research continues using mice as models for human disease or spinal cord injury. “The next step for us is to ask parallel questions of other parts of the brain and spinal cord, those involved in ALS and with spinal cord injuries,” according to Macklis. "In these cases, can we rebuild circuitry in the mammalian brain? I suspect that we can."

This study, coming so quickly on the heels of another report showing the functional integration of human embryonic stem cells into the mouse brain, suggests that embryonic stem cell research may indeed open new ways to treat brain disease or injury. Both studies, however, open the possibility that the use of technologies of brain regeneration will not stop with disease. As always, the growing power of medicine to treat disease is also an expansion of the possibility of human enhancement. All this if far in the future. But already, advocates of human enhancement have noticed its significance. See, for example, the re-posting of the original press release on Ray Kurweil's transhumanist blog.

The report, entitled “Transplanted Hypothalamic Neurons Restore Leptin Signaling and Ameliorate Obesity in db/db Mice,” appears in the November 25, 2011 issue of Science.

Ancient Humans: Violent? Caring?

A report in the November 21 issue of PNAS opens a sobering window into the lives and deaths of Ice Age humans. The report analyses a skull found in China and dating to 126,000 years ago and showing clear evidence of blunt force trauma.

[See photo, left. This is the right superolateral view of the Maba cranium showing the position (A) and detail (B) of the depressed lesion. Credit: University of the Witwatersrand.]

Was it aggression or an accident, deliberate violence or just an sharp but unlucky bump to the head? No one knows for sure. Based on comparison with similar findings, however, researchers suspect human-to-human violence.

One thing that makes this discovery stand out is its early date. Quite possibly, it is the earliest known evidence of human aggression against another human being.

The injury was not fatal. The trauma to the skull shows clear evidence of healing. For researchers, this healing is proof that the victim lived months and possibly years after the injury, quite possibly because of care offered by fellow Middle Pleistocene humans. If true, then the skull may be evidence of human caring as well as human violence.

According to Prof. Lynne Scheparz, one of the authors of the study, “this wound is very similar to what is observed today when someone is struck forcibly with a heavy blunt object. As such it joins a small sample of Ice Age humans with probable evidence of humanly induced trauma, and could possibly be the oldest example of interhuman aggression and human induced trauma documented.”

At the same time, the skull’s “remodelled, healed condition also indicates the survival of a serious brain injury, a circumstance that is increasingly documented for archaic and modern Homo through the Pleistocene,” according to Schepartz. In other words, this skull is not unusual in suggesting that ancient humans cared for each other after serious brain injury. As Schepartz puts it in a press release from the University of Witwatersrand, this individual “would have needed social support and help in terms of care and feeding to recover from this wound."

According to the report itself, “the lesion…appears most likely to have been the result of a localized, blunt force trauma, sufficiently strong to produce the concentric ridges, the external depression, and the internal bulge. At the same time, the bone was extensively remodeled…Such remodeling minimally takes several months to develop,” possibly longer.

According to the report, it “is probable that it [the injury] was the result of an interpersonal altercation, with blunt-force trauma, given its form, but accidental injury cannot be excluded. It may be the oldest such case known…”

The report provides a sobering picture of the past. A single skull provides what might be the oldest snapshot of human violence and human caring, a scant 14mm in length but a powerfully accurate view of the best and the worst in us.

The report, “New evidence of interhuman aggression and human induced trauma 126,000 years ago, was published in the November 21, 2011 issue of PNAS.

Stem Cells, Working Brains, and Human Enhancement

Research using human pluripotent stem cells—whether derived from an embryo or induced into a pluripotent state—holds great promise for regenerating parts of the human body by producing new cells to replace diseased or damaged cells. Nowhere is this potential more intriguing than in the human brain.

During the past decade, researchers have learned to turn human pluripotent cells into neurons. They have tested these neurons in cell cultures, where they seem to function like normal neurons. They have implanted these human neurons in mouse brains, where human cells thrive like normal cells. The big question is whether they do the work of brain cells. Long before cells are implanted in human brains, researchers want to know whether the cells will function properly in any working brain, starting with a mouse brain.

Now comes evidence that the implanted cells seem to be fully function, integrated in the basic process of the mouse brain. In the report published in the November 21 issue of PNAS, researchers at the University of Wisconsin report on their use of a new technology, optogenetics, to test the function of the implanted cells. This technology uses light rather than electricity to stimulate implanted neurons. The result, it is claimed, is the best evidence so far that implanted cells are integrated fully into the functioning brain, sending and receiving signals as part of living neural networks.

”We show for the first time that these transplanted cells can both listen and talk to surrounding neurons of the adult brain,” said lead author Jason P. Weick in a press release from the University.

By using optogenetics, this study provides evidence that implanted human neurons derived from pluripotent stem cells can become functionally integrated into systems of a living brain, sending and receiving signals from surrounding or “host” cells and interacting with brain circuitry in a way that is consistent with normal brain rhythms.

According to the paper published in PNAS, the neurons derived from pluripotent cells “can participate in and modulate neural network activity through functional synaptic integration, suggesting they are capable of contributing to neural network information processing…”

What’s more, the researchers discovered that optogenetics may someday have a clinical use far beyond its value as a research tool. The fact that implanted cells can be stimulated using a light signal may someday become part of the way stem cells are used on human patients. According to Su-Chun Zhang, also an author of the report, “You can imagine that if the transplanted cells don't behave as they should, you could use this system to modulate them using light.”

Still more challenges must be met before neurons derived from human pluripotent cells are implanted successfully in the human brain. But this study advances the field in a critically important way and provides strong evidence that implanted cells might one day take on the function of damaged cells in the living human brain.

If human brains can be regenerated even in highly limited ways, the consequences will be profound. The most obvious applications will be to treat patients who have lost some part of brain function due to stroke, brain injury, or disease.

And if that becomes possible, it is not hard to imagine that the same technology will be used to regenerate the brains of those whose only “disease” is aging. Furthermore, it is quite likely that at some point in the future, implanted neurons derived from pluripotent cells will be genetically modified first, perhaps to prevent disease but also perhaps to enhance the performance of the brain into which they become functionally integrated.

It is important to stress that treatment for complex disorders of the brain, such as Alzheimer’s Disease, are still a long way off. But this research is an important step, showing that the basic concept of stem cell treatment may provide one form of treatment. But is that becomes possible, it may also become possible to enhance the cognitive capacity of people without disease.

The milestone reported here is just one more step--of which there must be hundreds or thousands--leading us closer to the day when human brains might be regenerated or renewed. Few will object to the use of such treatments to restore functioning neurons to those with Huntington's disease or early onset Alzheimers. And if early onset Alzheimers, why not late onset? And if late onset dementia, why not age-related cognitive decline? At what point do we cross the line from therapy to enhancement, and does such a line even exist?

So while we stress that these treatments are not available today--and may never be--they will very likely come in time. And when they come, they will open the path for completely new ways to extend the functional lifespan of the human brain.
The report, entitled "Human embryonic stem cell-derived neurons adopt and regulate the activity of an established neural network," appeared in the Nov 21, 2011 issue of PNAS.

Religion and Nanotech: Problems Ahead?

Chris Toumey has just posted a nice summary of research on religion and attitudes toward nanotechnology. Toumey is a cultural anthropologist in the University of South Carolina NanoCenter, and what he reports is pretty sobering.

Toumey’s study summarizes seven recent research projects that explore the relationship between religious beliefs and attitudes toward nanotechnology. He cites a study by Brossard et al. entitled "Religiosity as a perceptual filter: examining processes of opinion formation about nanotechnology", which found that the "strength of religious beliefs is negatively related to support for funding of nanotechnology.”

One thing that concerns religious people about nanotechnology, Toumey says, is its possible link to transhumanism. He writes that “many religious persons worry that nanotechnology will contribute to re-defining human nature in ways that are amoral or dangerous.”

Underneath the fear of nanotechnology is a more fundamental fear of transhumanism. Religious people, says Toumey, “sense that transhumanist values are the enemy of religious values, and that nanotechnology, especially nanomedicine, is implicated in a transhumanist agenda.”

Toumey claims that of the seven studies he reviewed, six identified the religious objection to transhumanism as the basis for worries about nanotechnology. Not all six use the term “transhumanism,” but all refer explicitly to a deep anxiety that nanotechnology poses some sort of threat to human nature. Toumey writes: “Six of the seven religious reactions include a concern that nanotech will contribute to changing our sense of what it means to be human, and that this is clearly undesirable.”

All the more reason for religious scholars to take up the challenge of transhumanism and to disarm some of the anxiety. For me, at least, transhumanism is not to be feared. It is to be criticized theologically, not because it seeks to use technology to enhance human beings but because it sets its sights too low, or so I try to argue in Transhumanism and Transcendence.

A more complete version of Toumey’s review—"Seven Religious Reactions to Nanotechnology"—will appear in the December issue of NanoEthics.

New Book on “Transhumanism and Transcendence”

My latest book is Transhumanism and Transcendence: Christian Hope in an Age of Technological Enhancement. It is a collection of essays from leading Christian theologians responding to various aspects of transhumanism and of the growing potential for technology to “enhance” human beings. The book is on display for the first time at the book exhibits at the American Academy of Religion, 19-22 November 2011 in San Francisco. The publisher is Georgetown University Press.

On the back cover of the book, Philip Clayton comments:

This is the most important Christian debate on transhumanism that I have ever read. Those who prefer fawning acceptance or frightened rejection of human enhancement can find simplistic monographs aplenty. But if you want to think theologically about the transformation of humanity through technology—what's already here, and what lies ahead of us—this collection is mandatory reading.

I wrote the first and the last chapters of the book, framing the argument and summarizing the findings.
The eleven chapters in between are written by established scholars and younger thinkers, some of whom were finishing doctoral studies on transhumanism just as the book was being written.

Michael Burdett, for example, drew upon his studies at Oxford in writing about Francis Bacon, N. F. Fedorov, and Teilhard as early examples of transhumanist thinking. David Grumett, an emerging expert on Teilhard, follows Burdett with a deeper look at this pioneering theologian and scientist.

J. Jeanine Thweatt-Bates drew upon her doctoral work to criticize transhumanist thinking on gender, while Stephen Garner and Todd Daly provided fresh thinking about themes of cyborgs and extended lifespans in traditional Christian theology. Michael Spezio, a theologian who does advanced research in neuroscience, engages some of the projects of the Defense Advanced (DARPA).

Established scholars such as Ted Peters, Karen Lebacqz, Gerald McKenny, Brent Waters, and Celia Deane-Drummond also contribute chapters to this book. While all of them raise criticisms of transhumanism and of the growing use of technology for human enhancement, all recognize that transhuman poses a challenge for Christian theology.

Here’s one way to think about the challenge. Religion promises but technology delivers, so who needs religion anymore? For example, Christian theology holds up a promise of some form of life beyond the present. Technology, on the other hand, sees aging as a problem to be overcome, and it sets out to slow or even reverse it.

Whether it will truly succeed is, of course, debatable. But that’s not that point. The key question is where we place our hopes and what form of life do we hope for.

Through technology, transhumanists hope to transcend the limits of our biology. But is this the truest and highest form of human transcendence? It is not that technology is rejected or feared. But does teach us to settle for too little?

Studying Transhumanism and Religion

For several years now, the American Academy of Religion has included a “Transhumanism and Religion Group.” The next session of the group will be on Saturday, November 19, during the annual meeting of the AAR in San Francisco.

During our session, we will hear four papers. Brian Green will address the question, “Could Transhumanism Change Natural Law?” He will be followed by Michael Burdett, speaking on “New Jerusalem or the Tower of Babel?: Transhumanist Visions of the Future in Kurzweil, Rees, and Bostrom.”

The third paper will be presented by Amy Michelle DeBaets, addressing “The Transhuman Mystique: Feminism and the Discourses of Democratic Transhumanism.” Finally, Abbas Rattani will speak on “Transhumanism, Cosmetic Neurology, and Suffering.”

Following the discussion, Calvin Mercer will conduct a business meeting to make plans for next year’s session. Stay tuned here for a report on what happens on Saturday.

Human Nature, Human Self-Creation

When I spoke at the University of South Florida-St Petersburg last week, I summarized various ways in which the Human Genome Project has opened new perspectives on recent human evolution.

Evidence is mounting the anatomically modern humans (AMH) interbred with archaic humans, such as Neandertals, within the past 80,000 years and perhaps as recently as 30,000 years ago. Not only that, but in the view of some experts, this interbreeding was widespread, possibly more the rule than the exception.

The title of my talk was “Finding the Human in the Genome.” I presented visual images of early human art, including the recent report of the discovery of the 100,000 “artist workshop” in South Africa.

Looking at ancient art can be inspiring and moving, but for us today, the question comes back more forcefully than ever. What are we? Where are we going as a species? Are we in danger of destroying ourselves, not by violence but by modification, by engineering future humans that are not exactly human anymore?

I suggested that our past is somewhat more complex than we thought. Our future, likewise, is a bit more open-ended. We are not clearly defined at either end, either in our origins or in our destiny. As science discovers a complex past, technology opens an uncharted future.

At that point in the talk, I turned to the prescient words of Giovanni Pico della Mirandola, the author of the Oration on the Dignity of Man. Writing in 1486, Pico praises the greatness of the Creator, the “Great Artisan,” who creates human beings with no defined or determinate nature, except the need for self-creation:

Finally, the Great Artisan mandated that this creature who would receive nothing proper to himself shall have joint possession of whatever nature had been given to any other creature. He made man a creature of indeterminate and indifferent nature, and, placing him in the middle of the world, said to him "Adam, we give you no fixed place to live, no form that is peculiar to you, nor any function that is yours alone. According to your desires and judgment, you will have and possess whatever place to live, whatever form, and whatever functions you yourself choose. All other things have a limited and fixed nature prescribed and bounded by our laws. You, with no limit or no bound, may choose for yourself the limits and bounds of your nature. We have placed you at the world's center so that you may survey everything else in the world. We have made you neither of heavenly nor of earthly stuff, neither mortal nor immortal, so that with free choice and dignity, you may fashion yourself into whatever form you choose. To you is granted the power of degrading yourself into the lower forms of life, the beasts, and to you is granted the power, contained in your intellect and judgment, to be reborn into the higher forms, the divine.

According to Pico, God speaks these words to the newly created Adam and Eve and, in effect, to all of us. Then Pico comments: “Imagine! The great generosity of God! The happiness of man! To man it is allowed to be whatever he chooses to be!”

Now, thanks in part to recent science, we can see just how far Pico was right.

Archaic Interbreeding? So What?

Later this week, I will be speaking at the University of South Florida—Saint Petersburg in their lecture series, a Celebration of the Genome.” My topic is “Finding the Human in the Genome.”

I start with the obvious: Our knowledge of human biology is increasing rapidly, thanks in large part to the Human Genome Project. We can now compare the DNA of one human being with another and ask questions about similarities and differences. We can compare human DNA with the full genomes of chimps and other species.

Most interesting to me is that we can also compare the genome of anatomically modern humans with that of extinct forms of humanity, such as Neandertals or their recently discovered cousins, the Denisovans. What we have found is that in a real sense, they are not extinct at all because their DNA lives on in us.

That leads to something less obvious but more profound. The more we know about human biology, the less we know about human nature. Put another way, the more information we have, the less confident we are that we really know what we mean when we talk about “humanity.”

So what is going on here? Does it really bother anyone—besides me, that is, and perhaps only because I am, after all, a “theologian”? I am asking myself this question a lot these days. Does it really matter that our ancestors interbred with Neandertals and Denisovans and, as time will probably tell, many other forms of archaic humanity?

So what’s the big deal? In some ways I guess it’s like the high school student who runs a paternity test and learns that daddy isn’t daddy.

Or maybe it’s more like this. Years ago, I remember hearing Kári Stefánsson speaking to a roomful of scientists and introducing deCODE Genetics, the Iceland DNA database. He explained the reasons for the project, such as excellent health records, small genetic diversity, and superb genealogical records going back 1,000 years. We Icelanders need to sell more than fish, he said. We want to mine our DNA for all kinds of gene-disease information. Then Stefánsson mentioned that the information sometimes disproved the genealogies. Everyone laughed when he said: “We are not responsible for what our Viking ancestors did back then during the long Icelandic winters.”

Is that it? Is that all that’s happened here, just some forced revisions of the family tree? So what if my ancient ancestors were not exactly what I thought? It happened, after all, some 40,000-100,000 years ago. I am not responsible.

But I am affected. My biology is different from what I once thought. Perhaps I am healthier as a result of the ancient interbreeding, as at least one report has suggested.

More than that, I am coming to see human beings as biologically more diverse and more complicated that we once thought. The diversity part is a bit scary. We have not done well as a species in dealing with our differences.

The complexity part—that’s more of a mystery than a fear. I don’t claim to hear the voices of my Neandertal ancestors calling out from my DNA or reverberating through my metabolic processes. At least not yet.

Resveratrol and Human Enhancement

The debate over human enhancement may just have entered a new phase. Resveratrol, the natural compound found in red wine, has now been shown to improve the metabolism of human beings. While the word "enhancement" does not appear in the published report, the research will almost certainly be read by many as evidence that the use of resveratrol enhances human health and may even increase the human lifespan.

In the more prosaic language of the report, the news is simply this: Resveratrol, the natural compound found in red wine, has now been shown to improve the metabolism of human beings.

In the 2 November 2011 issue of the journal Cell Metabolism, researchers in the Netherlands and Switzerland report that a 30-day course of resveratrol brought about significant improvement in the basic metabolic functions of obese men.

Research using animals has shown that resveratrol can have a number of benefits related to how the body uses energy. In some species, resveratrol has been shown to increase average longevity. In other experiments involving lab animals, a reduction of 30-50% in calorie intake below what the animals normally eat has been shown to benefit the metabolism and extend the lifespan. Others studies show that resveratrol seems to mimic the effects of calorie restriction.

Now come hints that resveratrol may have some of these same effects on human beings. In the Cell Metabolism article, researchers report that the men who received the 150mg/day dose of resveratrol showed a number of changes that mimic what happens with calorie reduction. 150mg is about 100 times the amount of resveratrol found in an ordinary glass of red wine.

One of the researchers, Patrick Schrauwen, commented on the study in a press release issued by Maastricht University in the Netherlands: “We saw a lot of small effects, but consistently pointing in a good direction of improved metabolic health.” The study was concluded after 30 days, and so long-term benefits or side-effects are not known.

In particular, no one knows whether resveratrol has the capacity to extend the human lifespan. But the positive results published on 2 November will surely intensify the debate over the effects and the ethics of resveratrol.

In this study, resveratrol was administered to men who were obese but otherwise healthy. One way some bioethicists distinguish between morally legitimate “therapy” and morally questionable biomedical “enhancement” is by insisting that medicine must stick to treating those with disease. It is unethical, these bioethicists argue, to “enhance” people by using medicine to benefit those who are not sick. Their views are challenged by others who believe that technology should be used for human enhancement.

While this study may have observed that moral limit of treating only those with a “disease,” there is little reason to believe that the metabolic benefits of resveratrol are limited to those who are obese. On the contrary, there is every reason to think that this study will be used by advocates of human enhancement. In particular they will see this as the best evidence yet that resveratrol can be used to extend the human lifespan.

My prediction is that this study will encourage more widespread use of resveratrol. Most who use it will be seeking some form of enhancement if not an increase in longevity.

The article, “Calorie restriction-like effects of 30 days of resveratrol (resVidaTM) supplementation on energy metabolism and metabolic profile in obese humans,” appears in the 2 Nov 2011 issue of Cell Metabolism, where it is available free to the public.

Complicating the Family Tree

Our view of our past keeps getting more complicated. Our family tree, it turns out, is more of a twisted vine than a neatly linear branch.

Evidence keeps building by the day that our anatomically modern human (AMH) ancestors interbred with earlier forms of “archaic” humans. In the 31 Oct 2011 early online issue of PNAS, Pontus Skoglund and Mattias Jakobsson present evidence for the view that the genetic legacy of the Denisovans is wider than ever thought before.

First is was the Neandertals. This branch of the human family diverged from our own somewhere around 500,000 years ago. Somewhere between 100,000 and just 50,000 years ago, however, AMHs and Neandertals interbred successfully. The result lives on today in our genes. For many of us, our DNA is 2-3% from our Neanderthal ancestors. The Neandertals may be extinct, but their DNA lives on in every cell in the human body.

Then it was the Denisovans, a recently discovered branch of the human family more closely related to Neandertals than to us. What about AMH-Denisovan iInterbreeding? An international team of researchers led by Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology in Leipzig was able to extract Denisovan DNA from tiny fragments of remains. From the extracts, they reconstructed the Denisovan genome and compared it with the human genome. What they found was clear evidence of interbreeding. Some living human beings—those identified as Melanesians—carry Denisovan genes. That was reported in December 2010.

In September, however, Pääbo was joined by David Reich and Mark Stoneking and other colleagues in reporting that the legacy of Denisovan DNA extends beyond the Melanesians. It’s all over the islands that extend below Southeast Asia, including Australia. Not just Aboriginal Australians but Near Oceanians, Polynesians, Fijians, east Indonesians, and other groups as far as the Philippines are carriers of the Denisovan legacy.

According to this study, the genetic legacy of AMH-Denisovan admixture does not include East Asians. This led the authors to conjecture that there are at least two main waves of AMH migration into southeast Asia. The first wave interbred with Denisovans while the second, apparently, did not.

Their work appeared in the 7 Oct 2011 issue of the American Journal of Human Genetics. Reich discusses these findings in a video. Hint: start at minute 22:30.

But now a study published in the online early edition of the Proceedings of the National Academy of Sciences for the week of 31 Oct 2011 presents evidence that East Asians are also descended in part from the Denisovans. In the paper, the authors (Pontus Skoglund and Mattias Jakobsson) write that “we found a significant affinity between East Asians, particularly Southeast Asians, and the Denisova genome.”

Experts in the field will no doubt debate these findings. Just how widespread is the effect of AMH-Denisovan interbreeding? How widely did AMHs and archaic humans interbreed? To what extent does admixture provide any benefit? Does it shed any light on observable differences between different groups within the human family today?

According to Skoglund and Jakobsson, the “history of anatomically modern and archaic humans might be more complex than previously proposed.”

If our past is more complex than we thought, so is our present. What does it mean to be human? It no longer seems to mean that we are all part of a biological species. Whether we like to call ourselves "anatomically modern humans" (AMHs) or Homo sapiens, we are learning that the very concept of species is becoming unfocused by research. Should we speak of AMH-Denisovan "interbreeding" or "hybridization"? Does it matter? Are we separate species or one slightly-tangled humanity?

Science and Human Mystery

I have been reading Bernard McGinn, a foremost expert on the history of Christian spirituality and mystical theology. In a recent essay, he comments on “the importance of recognizing the mystery of human existence.”

In Christian theology, the mystery of the human is grounded in the mystery of God. In the fourth century, St. Gregory of Nyssa observed that human beings are in the image of God. Our nature mirrors God’s nature. If God is inexhaustible mystery, then what we are must always remain a mystery to ourselves. Otherwise, our knowledge of ourselves would serve as something of a key for us to figure God out, a kind of theological Rosetta stone.

What does this have to do with recent science? Some think that science finds facts and dissolves mysteries. McGinn suggests as much. He thinks that theology’s insistence on human mystery serves as a useful check on the de-mystifying pretensions of science.

I agree with McGinn about the theology of essential human mystery. But I disagree that science has a tendency to erase mystery. Sure, many people see science that way. But look again. The more we learn about human origins, the more we find that any clear notion of a distinct human species seems to unravel. The more scientists merge human and nonhuman organisms or blur the distinction between human and machine, the more we make ourselves mysterious.

If I am right, science increases mystery. At least that’s what I tried to suggest in the brief article I contributed to Science last February. For more, see my post for October 12, below.

That’s why I think McGinn is not quite right when he say this:

“If God is the ultimate mystery, man’s image-nature implies an essentially negative horizon, or limit, to all that can be scientifically discovered about humanity, however original, illuminating, and productive these findings may be. From this viewpoint, growing scientific information (i.e. more and more facts) about human nature (biological, psychological, and sociological) will always be limited by the realization that the true meaning of human existence rests in its status as an inexhaustible mystery. Scientific contributions to the deeper understanding of human nature are welcome and often useful in the task of human self-realization, but they take on a different color when viewed from the sapiential perspective of the “learned ignorance” (docta ignorantia) that recognizes the limits of what can be known and quantified about humanity. This recognition of the limits of science may not be an easy message for contemporaries to appreciate, enamored as we are by the amazing discoveries about homo sapiens made during the past century; but it is one of the most significant challenges that image dei anthropology offers to the present.”

McGinn’s essay is entitled “Humans as Imago Dei: Mystical Anthropology Then and Now.” It appears in Sources of Transformation: Revitalising Christian Spirituality, 2010.

A New Approach to Enhancement?

Some people object to human germline modification because they do not like the idea of one generation messing with the DNA of future generations. Even worse, they say, is modifying the genes for the sake of…gasp!...enhancement!

But now comes a tantalizing study in tomorrow’s issue of Nature hinting at the possibility that what we do to live longer may change the lifespan of our grandchildren. It’s only a hint—the research reported here involves the faithful nematode, Caenorhabditis elegans. By exposing one generation of these tiny worms to just three proteins, researchers in Anne Brunet’s lab at Stanford produced worms that live up to 30% longer. The surprising thing is that the enhanced lifespan was passed to the next 2-3 generations. The really surprising thing is that the lifespan of the C. elegans great-grandchildren was enhanced even though no DNA sequences were modified. In other words: germline enhancement without genetic modification.

How is that possible? Epigenetics. The three proteins changed the way the DNA is structured or packed without changing the DNA code itself. Such epigenetic changes can change the way genes are expressed. The effect can be dramatic—in this case, a 30% longer lifespan. What’s more, the epigenetic change can be passed to future generations. Most often, epigenetic changes are reset during reproduction. But in some cases, epigenetic modifications are passed to the next 2-3 generations. When that happens, the structure and the expression of DNA are changed even though the DNA sequence remains unchanged. Over time, however, the effect washes out so that the great-great-grandchildren are back to the starting point.

Will this epigenetics-to-lifespan relationship be found in human beings? Who knows. Again, it must be repeated: this research involves flatworms. Humans are just a bit more complicated. Already, however, Brunet’s lab is looking for something similar in mice and in African killfish.

Whether anything similar will be found in human beings, this research already suggests a truly interesting thought experiment. Suppose this leads someday to a human-application technology. Would it be opposed by those who object to human germline modification? Sure, future human beings would be changed without their consent. But no genes are changed, and the changes are not permanent.

Perhaps the more sobering thought is this. Maybe this research will lead to a startling discovery. Never mind some new technology. Might it turn out that what health-minded human beings normally do—eat their green vegetables, get their exercise—has the effect of enhancing their offspring by modifying the expression of their genes by means of generating inheritable epigenetic changes? Could be. If just three proteins make C. elegans progeny live 30% longer, just imagine how your dinner might change your grandchildren (assuming, of course, that you’re in your reproductive years or younger).

The article, “Transgenerational epigenetic inheritance of longevity in Caenorhabditis elegans,” appears in the October 20 issue of Nature.

Evolution and the Human Brain

How did the human brain become so complex so quickly? Did old genes learn new tricks? Or did new genes appear, bringing new functions?

A paper appearing today in PLoS Biology suggests that new genes play a bigger role than previously thought in explaining the complex functions of the human brain. Researchers at the University of Chicago Department of Ecology and Evolution reached this conclusion by comparing the age of genes with transcription data from humans and mice. Where are new genes most often expressed? In humans, it’s in the brain. Even more interestingly, it’s in the developing brain of the fetus and the infant.

One of the researchers, Yong E. Zhang, was motivated to ask these questions because he accompanied his pregnant wife to prenatal ultrasound appointment, according to a press release issued by the University of Chicago Medical Center. According to Zhang, “Newer genes are found in newer parts of the human brain.” The press release also quotes co-author Patrick Long: “What’s really surprising is that the evolutionary newest genes on the block act early….The primate-specific genes act before birth, even when a human embryo doesn’t look very different from a mouse embryo. But the actual differences are laid out early,” Long explained.

In the language of the PLoS Biology paper, the authors “observed an unexpected accelerated origination of new genes which are upregulated in the early developmental stages (fetal and infant) of human brains relative to mouse.” In other words, compared to all the genes in the human genome, younger genes are significantly more involved in those parts of the brain that make us distinctly human. More than that, these genes play a greater than expected role in prenatal and infant development, the very period in which the brains of humans develop so rapidly compared to the brains of other species.

How did these new genes arise? By all the various means by which new genes arise—by various processes of duplication and by de novo origination. Rather remarkably, the authors make this observation: “…young genes created by all major gene origination mechanisms tend to be upregulated in [the] fetal brain. Such generality suggests that a systematic force instead of a mutational bias associate with a specific origination mechanism contributed to the excess of young genes in the fetal brain.”

What “systematic force”? Clearly, the authors are not speculating about anything more than a statistical correlation. But their work will give rise to new questions for research. What role do these young genes actually play in the developing brain? What role did natural selection play in the evolution of these genes? Does this surprising correlation shed any light at all on our rapid rise as a species and the stunning complexity of the human brain?

The paper, "Accelerated Recruitment of New Brain Development Genes into the Human Genome," is published in the October 18 issue of PLoS Biology [10.1371/journal.pbio.1001179].

100,000 Years of Art

The awakening of human creativity is one of the great mysteries of our species. Even today we marvel at the artistic power of cave art, some of it dating back nearly 35,000 years ago. Musical instruments—flutes, at least—date back nearly as far. Beads, often made by carefully drilling a hole through shells, date to nearly 100,000 years ago.

And now comes evidence to suggest that painting goes back just as far. At least 100,000 years ago, about 40,000 years earlier than previously thought, human beings made pigments for paint through a process that is surprisingly complex.

In the October 14 edition of the journal Science, Christopher Henshilwood and his team present their analysis of the earliest known “artists’ workshop.” In the Blombos Cave in Cape Town, South Africa, they discovered a 100,000 year old ochre processing site. In two places in the cave, ochre was ground into fine powder, mixed with crushed quartz and other chemicals including charcoal and bone, and blended into a pigment mixture that was stored in two abalone shells. The pigment may have been used for painting, body decoration, or coloring of clothing.

"The recovery of these toolkits adds evidence for early technological and behavioural developments associated with humans and documents their deliberate planning, production and curation of pigmented compound and the use of containers. It also demonstrates that humans had an elementary knowledge of chemistry and the ability for long-term planning 100,000 years ago," concludes Henshilwood in a press release issued by the University of the Witwatersrand in Johannesburg. The article, "A 100,000-Year-Old Ochre-Processing Workshop at Blombos Cave, South Africa," appears in the October 14 issue of Science.

What is fascinating is how early all this occurred and just how complex the process was. It involved careful planning over time. It included surprisingly sophistical technology (one is tempted to say “chemical engineering”). Why? What was stirring then, and how are we still inventing new ways to release the human imagination?

Still wondering..."What Defines Us?"

Last February the editors of Science marked the 10th anniversary of the publication of the complete human genome. They invited a dozen or so people to contribute short reflections on the meaning of this milestone.

I was given 250 words for my article, entitled “What Defines Us?” In that small space I tried to suggest two things. First I noted a simple irony: As we gain more scientific information about our genome and our evolution, the philosophical and religious concepts of humanity become blurred or defocused. Second, I suggested that this defocusing need not be a cause for discomfort. Precisely because we are humans—whatever exactly that means anymore—we switch almost immediately from discomfort to wonder and excitement. The quick switch is what makes us human. I ended by asking: “Who are we, and where will we go next?”

It is as if we are making ourselves up as we go along. Recent discoveries in human evolution intimate just such a view. Anatomically modern humans are now believed to have interbred with Neandertals and with the more recently discovered Denisovans. Many of us carry the DNA of these extinct forms of humanity in our own genome. In that sense they are not distinct at all but live on in every cell of our bodies. More recently, it has been suggested that similar interbreeding occurred in sub-Saharan Africa.

Interestingly, it has also been suggested that interbreeding enhanced us. In August, a research article in Science suggested that our immune systems are more resilient than they might have been. Why? Because our ancestors interbred with Neandertals and Denisovans.

The evolutionary tree of humanity is beginning to look less like a tree and more like a tangled vine. And now we are led to wonder whether it is the tangle that enhances us. What makes us less clearly Homo sapiens seems, paradoxically, to make us more extraordinary as a species. Well…we’re running far ahead of the science here, but (as I suggested in Science), wondering is what makes us human. It’s not just the DNA; it’s what we dare to do with it.

I have been thinking about this recently because I will be speaking on November 10 on this very topic at the University of South Florida Saint Petersburg. They have planned an exciting lecture series, Festival of the Genome: Celebrating the 10th Anniversary of the Sequencing of the Human Genome, showcasing various perspectives on human genome research.