Introduction

For the last day and a half I have been attending the Sacker Colloquium entitled In the Light of Evolution IV: The Human Condition. Overall, it has been quite interesting, despite some disappointing talks. I intend with this post to briefly describe some of the more interesting talks that have occurred.

Opening Talk — E. O. Wilson

The opening talk of the colloquium was given by E. O. Wilson, mainly regarding the 4 great books of Darwin. The most distinctive claim he made — in addition to numerous anecdotes and facts about Darwin and other things — was that biological knowledge is now firm enough to be called a body of laws. In particular, he had in mind first that biological processes are all subject to the laws of physics and chemistry, and second that diversity and processes are the result of natural selection. While I do not know nearly enough biology to comment on the correctness of these principles, they do seem to make a lot of sense. Unfortunately (though perhaps by design) the talk did not present detailed evidence for the claims. The more important thing, however, is the directional proposal he presented. That is, he promoted focus on the question of the reason for the rarity of transitions.

An Introduction to Hominin Evolution — Bernard Wood

Bernard Wood gave an interesting talk that highlighted some of the potential pitfalls in hominin(e) taxonomy that I had not previously considered. Specifically, he was concerned about the importance of extinct branches of the tree of life for placing fossils. One such example that was recently discovered was ar. ramidus. This fossil was billed as the most recent discovered common ancestor of chimpanzees and humans, but there are other things to consider. That is, there is definitive reason to place ramidus as a direct ancestor to modern humans as opposed to on a branch that left the directly ancestral track between the chimp/human split. The point of the talk was to support a more detailed study of morphology in taxonomy.

Peopling the Planet Out of Africa — Doug Wallace

In an attempt to provide a comprehensive story of what drives the evolution of biological complexity, Doug Wallace presented a story based on energy. Drawing a parallel with thermodynamics and the natural decay of complexity in the absence of energy flux, he presented a view where biological adaptation was focused on aspects of energy acquisition and use. Biological niches are basically adaptations to caches of energy, regional adaptations are adaptations to energy distribution, and individual adaptations are in response to local energy variations. In order to support this, he focused on the role of mitochondria and mitochondrial DNA. The major tool for differing scales of adaptation, he argued, were the rapid mutation of mitochondrial DNA. I wish I could provide more details of this talk, but it was very technical and very fast.

Modern Human Evolutionary History in Africa — Sarah Tishkoff

Another interesting talk regarded the application of genetic tools to understanding human history. Sarah Tishkoff presented work she was involved in regarding this, especially with regard to identifying genetic differences in groups across Africa. In particular, she focused on the history of lactose tolerance/intolerance in various sub-populations. Through a variety of techniques, she was able to identify three separate developments of mutations promoting lactose tolerance, two of which are distinct from the mutations promoting lactose tolerance in Northern European populations. The ability to identify the coevolution and spread of these genetic features was fascinating.

Population Genetic Inference in the Personal Genome Era — Carlos Bustamante

Though this was yet another very technical talk for which I do not have a proper background to relate in detail, Carlos Bustamante presented some work which was still fascinating even in a broad-strokes picture. His work was an attempt to derive historical details from individual genetics. One particularly interesting (and scary) application was the ability to identify very reliably the country of origin in Europe of someone (even within as little as 200 miles) given their genetic heritage. The basic tool for this was Principle Component analyses, but it did sound like he and his collaborators had developed some even more effective tools for similar analyses. As I said before, this was quite interesting, but also very scary in a Gattaca sort of way.

Uniquely Human Changes in Sialic Acid Biology — Ajit Varki

The second of the talks on the second day of the conference was, in my opinion, quite awesome. Ajit Varki presented work of him and various collaborators regarding an evolutionary picture of human genetics and immunology. Apparently, there are two common markers for cells in various organisms — Neu5Ac and Neu5Gc. Humans, unlike chimpanzees and most other organisms no longer exhibit Neu5Gc. However, it was this that allowed self-cells to be readily identified. Without it, many pathogens became more effective at impersonating self-cells. So the human body developed other means for identifying pathogens through marking Neu5Gc, which many still contain. But human cells are also capable of “eating” Neu5Gc, which is present in many red meat and milk products.

Moreover, the identification and eradication mechanisms based on Neu5Gc also seem to be connected with a wide variety of chronic disorders, including autoimmune diseases, cancers, and many more. This seems to be a very important discovery, and I would love to read more about it.

There are three more talks to come yet this afternoon, so I may be posting an update later today if they seem worth mentioning.