Can you spell g-a-u-t-e-n-g-e-n-s-i-s?

It seems like barely a few weeks have gone by since the last public announcement about the discovery and identification of a new fossil human ancestor and here we are again, looking at a new face in the family line up.

Meet Homo gautengensis.

Recently we were “warned” that the discovery of several proto humans were about to hit the headlines. The first of these is now getting the limelight; a new member to the genus Homo no less.

Homo gautengensis lived in what is now South Africa. Gauteng refers to a province in that country, and a term in the local Sesotho language meaning ‘place of gold.’

 Photo courtesy of Darren Curnoe

The preliminary information available through public channels at the time of writing indicate that this new species of hominid, which  measured about three feet tall and weighed around 110 pounds, was capable of walking upright as well as moving around in the trees. They lived from about 2 million years ago to 600,000 years ago. According to the researchers involved in this discovery, Homo gautengensis predated Homo habilis, officially still listed as the oldest known tool making and using human. As you will see below, there are other researchers who claim that Homo habilis had a much greater time depth. This headline grabbing statement will, no doubt, generate an interesting discussion.

This may now change as more context information becomes available. According to Dr. Darren Curnoe thinks it is highly likely that these hominids ‘produced and used stone tools and may even have made fire.” The presence of burnt bones found in association with the human remains points to this alleged use and mastery of fire.

More information will be published in an upcoming issue of the journal HOMO – Journal of Comparative Human Biology. Until then, this seems to be the extent of what the general public knows. What is certainly interesting to note here is that, while the announcement is to be made soon, the skull fragments were found in 1976 in the famous Sterkfontein caves. According to a University of New South Wales publication,

“The surprise finding was based on a partial skull – known by its museum catalogue number Stw 53 – along with two other partial skulls, several jaws, teeth and other bones found at various times at Sterkfontein and other nearby caves.”

This is not the end of the story. As they say in late night commercials: “but wait there is more…”  What is the broader picture here? We all know that when it comes to the study of early human ancestors, hyperbole often abounds in press releases and subsequent newspaper articles. With that in mind, be prepared to read headlines in which the totally incorrect terminology of “missing link” will re-appear. There will also be claims that our understanding of human has been “severely shaken,”  as it was claimed in other cases, again and again. You get the picture.

Homo erectus
Creative Commons License Photo credit Thomas Roche

Aside from all this predictable hoopla, we do have a chronological range (2 million to 600,000 years ago) and a place (Gauteng province, South Africa). Who else was around during that timeframe? As it turns out, quite a few hominids were around during that time span, all members of the genus Homo. Homo rudolfensis lived in East Africa from 1.9 to 1.8 million years ago; Homo habilis lived in Eastern and Southern Africa from 2.4 to 1.4 million years ago; Homo erectus lived in Northern, Eastern and Southern Africa as well as parts of Asia; Homo heidelbergensis lived in Europe, and possibly Asia and Africa from 700,000 to 200,000 years ago.

It looks like the place was crowded. In a way it was, with many more species of hominids present on our planet, mainly Africa, than there are today. In another way, it was not; we should not conjure up images of all these ancient hominids bumping into each other and stepping aside to let the others pass as if it were a busy pedestrian crossing in downtown Tokyo. Chances are that most may not have seen other species, and, if they did, were they aware that these others were different?

The earliest accepted evidence of using and controlling fire dates back to 790,000 years ago, at a site in Israel. If this find is pegged closer to the 2 million years ago mark, this would move the marker of fire use back in time considerably. We are not yet at stage of the game yet to make that call.
I wonder what the next announcement will bring.

Stay tuned.

We’ll, I’ll be a Monkey’s Uncle. Or an Orangutan’s.

Our Guest blogger today is Dr. Todd Disotell, a professor of anthropology and a molecular primatologist at New York University’s Center for the Study of Human Origins. He will be speaking at HMNS on Feb. 9 at 6:30 p.m. about new molecular analytical techniques and how mapping whole genome sequences has affected what we know about the past. In his blog below, Dr. Disotell debates a recently proposed theory that humans are more closely related to orangutans than chimpanzees – a theory he disagrees with.

Posing for the Camera
Creative Commons License photo credit: jimbowen0306

This past summer upon the publication of a paper by a colleague, I found myself at the intersection of a 25 year old hypothesis, the latest research in genomics and bioinformatics, and popular culture.  Jeffrey Schwartz of the University of Pittsburgh and his coauthor, John Grehan of the Buffalo Museum of Science published an updated version of their hypothesis that orangutans are more closely related to humans than are chimpanzees in the Journal of Biogeography.  This intrigued me because in my final year of graduate school, my advisors and I published one of the earliest papers utilizing DNA sequence data supporting the growing consensus that chimpanzees were our closest relative, followed by gorillas, and much more distantly orangutans.

Perhaps due to my working in New York City, a producer from the Daily Show with Jon Stewart called me at my office and wanted to know if I was willing to be interviewed about Schwartz’s hypothesis.  As a fan I readily agreed and correspondent John Oliver was dispatched to my laboratory to interview me.  During the course of the interview in which I stated that the hypothesis flew in the face of all known genetic evidence, I opined that I would at least get to write a counter paper and perhaps a counter-counter paper if Schwartz responded.  That got me thinking about newly available genomic data that was now available in various databases which had not been fully analyzed.

Confused chimp
Creative Commons License photo credit:
Tambako the Jaguar

I then downloaded the complete genome alignments that included human, chimpanzee, gorilla, orangutan, macaque, marmoset, lemur, and galago.  After writing a series of Python scripts (an open source computer programming language) to parse and reformat the masses of sequence data, I chose the first 1 million bases of each chromosome for which all of the above species were represented.  I then used well characterized statistical and analytical techniques to infer the evolutionary history of each DNA region.  Not surprising to me, the analysis of each region convincingly rejects the hypothesis that orangutans are more closely related to humans than are chimpanzees.  Furthermore, when these 30 million DNA bases are used to estimate the time of divergence between humans, chimpanzees, and orangutans using molecular clock techniques, the orangutan appears to have diverged at over twice the age chimpanzees have from humans.

These results are not at all surprising to the absolute majority of paleoanthropologists and evolutionary primatologists.  However, it is still worthwhile to occasionally revisit theories and hypotheses that we now take for granted when new data are generated and new analytical techniques are developed.  In this genomic age, as the genomes of more and more species and even individuals within species are being sequenced, a whole new class and scale of analyses can be carried out from the keyboard.

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Check out Dr. Disotell’s lecture, “Times Are a-Changin': New Methods Tell A New Tale of Primate Evolution” at HMNS on Feb. 9 – get tickets here!