Anthropology.net

A summary of Yoel Rak’s talk at the last month meeting of the Paleoanthropology Society in Vancouver, Canada has surfaced in a National Geographic news article from several days ago. Yoel Rak and William Hylander analyzed the anatomy of the Neandertal face and inferred what that coulda meant as far as Neandertal dietary behavior. Did they take quaint bites like a sophisticated aristocrat or were they ruthless wide mouth ogres? If you read the title of this post you’d know the answer to that.

Rak presented his findings, specifically focusing on how the forward-positioned molars and an unusually large mandibular notches allowed Neandertals to gape widely. I’ve put up a photo of La Ferrassie 1 to you right. La Ferrassie 1 is a Neandertal skull found in 1909 in France that shows both traits.

“The scientists believe the large space behind Neandertals’ molars created a geometry that allowed them to take extremely large bites… perhaps an adaptation to the size of the food Neandertals ate, the researchers said.”

This sort of conclusion reeks of adaptionist story telling. I remember reading a similar study that analyzed the form of a horse’s mouth and concluded that it is perfectly adapted to eat apples. Just silly to think of selection and adaptation this way. Anyone one else who shares this sentiment will also appreciate Alan Mann‘s snarky commentary, which really drives home the ridiculous nature behind this study. Mann said,

“They didn’t have to put a whole [animal] leg in their mouths.”

The news article goes on to express Mann’s opinion, on how the gape size expanded as a function of brain expansion.

“What has changed is the architecture that we begin to see in modern humans, where the face and the braincase have different kinds of structural relationships…This has produced a change in our ability to open our mouths.”

Recently, I introduced related studies that showed how Neandertals may have eaten plants and how form may not equal function in regards to hominin mastication anatomy. I have some concerns with both studies, but that doesn’t mean they don’t provide applicable criticisms towards Rak and Hylander’s conclusions on Neandertal dietary behavior.

Scientific American has a news piece explaining the implications of one of the new studies on the human genome that I reported on last week. In a nutshell, the news piece explains how the identification of 250 new regions throughout the genome impacts the current human reference genome… raising concerns that reference genome may be faulty—and that there may actually be yet-to-be-uncovered genes missing from it.

Human Genome Project assembled this reference genome I am referring to in 2003. The reference genome is an amalgamation of sequences from four people (two men and two women) and still has gaps in it. I look forward to seeing if amendments will be made to the reference genome based upon these findings. If you think about it, it is gonna be a really big challenge to assemble a more complete reference genome. To recap the conclusions of the study,

“The researchers identified 1,695 instances of structural variations, 800 of which had not been previously reported. Fifty percent of the regions affected by these mutations showed up in more than one of the people studied. Forty percent of the 525 regions found to be missing from the reference genome were due to copy number variations, which means that a crop of yet-to-be-discovered genes may be hiding within them.”

With so many variants floating around, both large ones like copy number variations and small ones like SNPs, the reference genome must be assembled with the most common sets of alleles. That’s gonna take a lot of work, the genomes of many people from different ethnic backgrounds will need to be sequenced, assembled and folded into the current model.