Old DNA, New Tricks

Over the past decade, researchers have learned to reconstruct ancient DNA from fossils.  In December 2013, we were stunned to learn that refinements in techniques made it possible to restore human DNA from as far back as 400,000 years ago. 

Quickly on the heels of that advance, another new development has been announced in the 27-31 January online edition of PNAS.  Scientists at the University of Uppsala, in cooperation with the pioneering team in Leipzig, have developed a way to separate the old DNA sequences from contamination.

Photo Credit: Creative Commons, posted by Archaeogenetics, no restrictions.

Why is that important?  Because contamintion is a leading problem when it comes to reconstructing ancient DNA.  Literally thousands of fossils fill draws and shelves in museums around the world.  They contain DNA, too much of it, in fact, to be of any use.  Bits of ancient DNA are surrounded by more modern DNA from humans and from other organisms.  Now, researchers have learned to separate the old from the new. 
 
What makes the new breakthrough exciting is that now, at least some DNA information from many of these old fossils might be retreivable. 

"Many extremely interesting DNA data sets from ancient humans never see the light of day because of contamination. The idea behind this method was to change that," says Pontus Skoglund, a lead author at Uppsala University.
 
To test the new technique, the researchers used it to reconstruct the mitochondrial DNA from a previously unusuable Neandertal bone from the Altai Mountain region of Siberia.  The sample compared well with other known Neandertal DNA sequences in contrast to more modern humans.
 
It is hard to predict just where this new technology will lead.  At the very least, it seems to unlock the file boxes of museums throughout the world.  Previously discovered fossils, some of them very well dated, might be analyzed for the DNA.  Who knows what we will learn.

"There are many really interesting ancient human remains that we can rescue from severe contamination with this method. And the method is not limited to Neanderthals, even remains of anatomically modern humans that are contaminated by modern-day humans can be rescued," says co-investiagor Mattias Jakobsson in a press release from the University of Uppsala.
 
The new technique is described in a paper entitled "Separating endogenous ancient DNA from modern day contamination in a Siberian Neandertal." Skoglund, P.; Jakobsson, M.; Northoff, B.H.; Pääbo, S.; Krause, J.; Shunkov, M.V.; Derevianko, A.P; PNAS Online Early Edition the week of Jan 27-Jan31, 2014.

Is Neandertal Technology Still in Use Today?

Those primitive Neandertals may not have been so primitive after all.  Some 50,000 years ago, they were using a highly crafted bone tool virtually identical to a tool in use by human leather-workers today.

The tool is called a lissoir, was made by Neandertals living in southwestern France long before the arrival of the people we like to call “anatomically modern humans.”  The discovery, reported in the August 16, 2013 online issue of PNAS, is sure to fuel the debate over the cultural sophistication of the Neandertals.

Caption: Four views of the most complete lissoir found during excavations at the Neandertal site of Abri Peyrony.  Credit: Image courtesy of the Abri Peyrony and Pech-de-l’Azé I Projects.

Ever since their discovery over 150 years ago, Neandertals have been seen as “cavemen,” primitive in every respect compared to us “modern” humans who replaced them.


But in recent decades, the cultural achievements of Neandertals have been recognized.  Even so, the debate continues.  Did they learn more advanced technology from the modern human invaders of Europe and Asia, or did they develop it on their own?  The new findings lends support to the view that Neandertals were able to create and invent on their own. 

Neandertals were very likely the first to use sophisticated bone tools in Europe.  The tool found in France was made from the rib bone of red deer or possibly reindeer.  Making it required breaking, grinding, and polishing.  It shows evidence of being used to work leather, much like similar tools today.  When rubbed against an animal hide, it makes the leather soft, shiny, and more water resistant.

"For now the bone tools from these two sites are one of the better pieces of evidence we have for Neandertals developing on their own a technology previously associated only with modern humans", explains Shannon McPherron of the Max Planck Institute for Evolutionary Anthropology in Leipzig according to a press release from the Institute. 

Tools like this first appear in Africa much earlier.  But this new finding raising intriguing questions.  Did “modern” humans bring this technology from Africa and pass it to Neandertals prior to 50,000 years ago? Is there a technology transfer around the same time as modern/Neandertal interbreeding?  Or did Neandertals invent this technology on their own and transfer it to the modern humans who began to arrive in Europe around 40,000 years ago? 

"If Neandertals developed this type of bone tool on their own, it is possible that modern humans then acquired this technology from Neandertals. Modern humans seem to have entered Europe with pointed bone tools only, and soon after started to make lissoirs. This is the first possible evidence for transmission from Neandertals to our direct ancestors," says Marie Soressi of Leiden University in The Netherlands, part of the team of researchers who made this discovery.

"Lissoirs like these are a great tool for working leather, so much so that 50 thousand years after Neandertals made these, I was able to purchase a new one on the Internet from a site selling tools for traditional crafts," says Soressi. "It shows that this tool was so efficient that it had been maintained through time with almost no change. It might be one or perhaps even the only heritage from Neandertal times that our society is still using today."

Neandertals at this time were making sophisticated stone tools.  But these tools were made of bone because bone can is more adaptable for certain uses.  According to McPherron, "here we have an example of Neandertals taking advantage of the pliability and flexibility of bone to shape it in new ways to do things stone could not do."

The deeper question that lies behind this research is whether “modern humans” burst on the scene suddenly as a unique phenomenon of evolution, or whether the process of becoming human is more gradual and more widely distributed than we once thought.  

The research reported here was conducted by teams from Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and the University of Leiden in the Netherlands.  The article, entitled “Neandertals made the first specialized bone tools in Europe,” appears in the August 16, 2013 online edition of the Proceedings of the National Academy of Sciences.
 

Did Neandertals Wear Ornaments?

A small but tantalizing find provides further evidence for Neandertal culture.  Working in the foothills of the Alps just north of Venice, Italy, researchers have discovered and analyzed a small marine shell that originally came from about 60 miles away.  It was thinly coated with a dark red substance that turns out to be pure hematite and was most likely used as a pigment.  One possibility is that the shell was used as an ornament.

The paper, freely available online in the journal PLoS One, dates the shell’s pigmentation to a period just before 45,000 years ago, right before the arrival of so-called “modern” humans in Europe. 

Photo Caption: A shell possibly "painted" by Neandertals about 45,000 years ago.  Photo available from PLoS One.

According to the paper, “deliberate transport and coloring of an exotic object, and perhaps its use as pendant, was a component of Neandertal symbolic culture, well before the earliest appearance of the anatomically modern humans in Europe.”

Quoting more of the paper, “this discovery adds to the ever-increasing evidence that Neandertals had symbolic items as part of their culture.”

Debates about Neandertal culture have intensified recently, in part because of genetic evidence of interbreeding between Neandertals and the modern humans coming into Asia and Europe.  While these modern humans began their migration out of Africa about 80,000 years ago and probably interbred around 55,000 years ago, they did not reach Europe until more like 40,000 years ago.  If all these dates hold up in future research, this shell does provide a small but intriguing hint about the culture of Neandertals at just about the time of their encounter with “modern” humans. 

So who exactly is modern?  The differences between ourselves (the humans we like to call “modern”) and the Neandertals are not as great than we once imagined.  The paper ends with these words: “Future discoveries will only add to our appreciation of Neandertals shared capacities with us.”

The paper, entitled "An Ochered Fossil Marine Shell From the Mousterian of FumaneCave, Italy," appears in the current issue of PLoS One and is freely available online.