A Pinky’s Promise

In the summer of 2008, a multi-national team of Russian, European and American researchers found a small bone at a remote cave site in Siberia. At the time of discovery researchers had been working at the Denisova cave, located in the Altai Mountains in southern Siberia for several years already. Moreover, the cave was open to visitors as early as 2000, when it was listed on the program of The Second International Conference on Bioinformatics of Genome Regulation and Structure, held in Novosibirsk.

Initially, the discovery of a bone did not raise eyebrows, as the presence of Neanderthal people in the area between 48,000 and 30,000 years ago was a well-established fact. Interesting thus far, but nothing out of the ordinary.

As it turns out the small bone, identified as one of the bones in one’s pinky, held some surprises. Scientists at the Max Planck Institute in Leipzig extracted DNA – specifically mitochondrial DNA — and concluded that this type of DNA represented “a hitherto unknown type of hominin mtDNA that shares a common ancestor with anatomically modern human and Neanderthal mtDNAs about 1.0 million years ago.”  [For those scratching their head over the term “hominin,” this refers to extinct members of the human lineage.] So we are looking at one bone of a previously unknown hominin? Possibly. Or maybe not. 

The notion that we had several hominins living side by side, modern humans, Neanderthalers, and possibly this third species, should not come as a surprise. This happened quite frequently in our past; our existence today as the sole representatives of the human lineage is seen as an exception rather than the rule. What would be remarkable is that we have evidence of a human ancestor or close relative whom we did not know existed.

The latter realization has created a lot of buzz among those interested in human evolution. As is always the case with this type of endeavor, we need to be cautious and outline what we know, what the limits of our understanding are and where we shift from scientifically supportable reconstructions to pure speculation. A number of topics need further clarification here.

First, where does the owner of the bone fit in on the family tree, especially compared to us and to Neanderthals?

 Location of Denisova Cave and presumed place
on the family tree of the Denisova Cave specimen.

Researchers compared the Denisova mitochondrial DNA to complete mitochondrial sequences from 54 modern humans as well as a human who lived in Siberia about 30,000 years ago, six Neanderthals from more than 40,000 years ago, a modern pygmy chimpanzee and a modern common chimp. The results indicated that there are about 400 differences between us and the DNA in the pinky. This is twice as many differences as exist between modern human and Neanderthal DNA. This has led researchers to suggest that our last common ancestor lived about 1 million years ago, about twice as long ago as the common ancestor to us and Neanderthalers.

A second question that begs an answer is:  “what creature does this DNA belong to?” Various scenarios have been suggested here. It is possible, that we are dealing with a new species, neither modern human nor Neanderthal. Secondly, it could be a Neanderthal child, resulting from a union between a Neanderthal and an unknown species. Lastly it could be a Neanderthal individual, carrying variations in genetic make up thus far not identified in predominantly European samples.

The possibility that we are dealing with a completely new species is the most exciting. It is also one that most people caution us against. “Too soon,” “not enough material,” are some of the more common reactions. Others disagree and support the notion that this is a different species. This argument between those who see few species in the archaeological record (“lumpers”) and those who prefer a larger number of species (“splitters”) is one that has been described in a previous blog.

Skeleton of an alleged
Homo sapiens – Neanderthal
hybrid child found in Portugal.
Image courtesy of donsmaps

The scenario raising the possibility of an interspecies affair (between Neanderthal and another species) is favored by some, who see parallels with an alleged Neanderthal – modern human hybrid child found in Portugal. In this case, however, we would be looking at a child of a Neanderthal and a yet unknown species. This still implies that we had an unknown creature wandering the Siberian wilds, one whose genetics were inherited by a mixed offspring. In other words, this scenario still requires acceptance of the existence of an unknown species.

Finally it is conceivable that the breath of Neanderthal genetic variation is such that we have not mapped all of it. Given that most research on Neanderthals has concentrated on European materials, rather than Siberian, perhaps these Eastern Neanderthals carried in them a number of genetic variations that hark back to the original population in Africa. This would support the third option, one which identifies this pinky bone as belonging to a Neanderthal individual, albeit it with genetic markers not encountered in European samples. If identified as such, then this bone would reinforce the notion that Neanderthals occupied a much larger territory than originally assumed.

This discovery is meaningful in several ways. It illustrates that science marches on, providing answers to questions and, in the process, raises additional questions. It also shows how meticulous one has to work as an archaeologist or paleoanthropologist. One small pinky bone has provided us with a “what-in-the-world-is-this?” moment. The decision to perform a DNA test warns us not to be complacent. Up until recently, the party line about who was around some 40,000 years ago would have been answered with Homo sapiens or Neanderthalers, and nobody else. We are now forced to entertain the possibility of a hitherto unknown species living side by side with the other two. That is the promise this one tiny pinky bone holds.

A few final comments and thoughts.

What most articles I have read do not elaborate on is the fact that research is now happening in Siberia. This is a huge territory, difficult to access for all kinds of reasons. When discoveries like these are made, we should not be surprised that they generate questions we cannot answer yet, as researchers are accessing a territory close to the size of the US (a fact appreciated more than a century ago). I hope this discovery will result in greater support for research in the region. One day I am sure we will have a much clearer picture of what it is we are dealing with here.

Pinky promise.

Woolly mammoths to walk the earth again?

Thats right. Those giant, tusked behemoths could one day soon walk among us again. Maybe I should start at the beginning.

st petersburg 2008 - 218.JPG
© Photo credit: Florent Herry

In 2007, a reindeer breeder in the Yamal Peninsula of Siberia named Yuri Khudi discovered a one month old baby woolly mammoth. The baby mammoth, dubbed Lyuba, is roughly 40,000 years old and almost perfectly preserved (missing only her fur and toenails.) Lyuba either suffocated by sinking in mud or drowned in a muddy river.

Large amounts of mud were found in her mouth, trunk and trachea, suggesting that she asphyxiated. This sealed out oxygen and microbes that normally break down soft tissue and helped keep Lyuba perserved. Her body then dehydrated and shrunk to about half of her normal size. Lyuba now stands about waist high on the average person. The permafrost of Siberia then covered her and kept her in pristine condition until she was uncovered 40,000 years later.

Interested? So was National Geographic. They created a documentary about Lyula, the best-preserved baby mammoth ever discovered. Waking the Baby Mammoth premieres this Sunday, April 26, at 8 p.m. Central time, and follows Yuri’s amazing find and the fascinating process of discovery as scientists work to unravel Lyula’s mysteries.  (Check out the video preview below)They investigate the body of the mammoth, learning how she briefly lived and theorizing how she died. The documentary includes CGI graphics that help show how Lyuba and her family might have looked as they survived the harsh conditions of Siberia during the ice age.

Some other things you might not know about wooly mammoths:

The word “mammoth” is thought to have originated from an old Vogul word for “earth.”

Woolly Mammoths began dying out about 10,000 years ago, around the end of the ice age. A small population of dwarfed mammoths survived in Alaska until roughly 3,700 years ago; however, the majority died out long before then.

The first largely intact frozen mammoth carcass was discovered in 1799 in Siberia.

One of the longest mammoth tusks ever found was 16 feet long and weighed more than 200 pounds.

asian-elephant
 © Photo credit:
robertpaulyoung

Mammoths are very closely related to the Asian Elephant (they share 99.4 percent of their DNA.) It is possible to take the sperm from a mammoth and impregnant the egg of an elephant, and use a female elephant to incubate. This would give birth to a mammoth/elephant hybrid.

From there, it would be possible to impregnate the hybrid to create an offspring that was even more closely related to the ancient mammoths. In a similar process, you could also take a woolly mammoth egg and clone it to create  a woolly mammoth.

The woolly mammoth genome was the first genome to be reconstructed from an extinct animal It has 4.7 billion base pairs and is the largest known mammal genome.

Science Doesn’t Sleep (6.25.08)

I just can't get a break

Mmmmm…anti-inflammatories.
Creative Commons License photo credit: jslander

So here’s what went down after you logged off.

Sprained ankle? Eat two slices and call me in the morning. Researchers at the University of Bonn claim that the spice oregano – commonly found in pizza – can reduce inflammation.

Siberian mummies are revealing fascinting insights into a culture that warred with the ancient Greeks – including the earliest documented example of cancer.

You don’t want to know what happens when he blows his nose. A computer scientist has turned his face into a remote control - using facial recognition technology. 

Apparently, we’re all mutants. Researchers at Johns Hopkins have discovered that your genome changes during the course of your life.

The Linnean Society – named for famed naturalist Carl Linnaeus - has put its entire collection of plants and insects online. You can zoom in on these beautiful flash photos for an amazing look at all of the tiniest details. (Via)