Today has been very exciting, even though I have had some reservations about the talks. Usually I like shorter than one hour talks, but the length here is limited to 20 minutes, and speakers are really rushing through things. Given that, I had a really hard time following the morning lectures, which were on the interesting but (for me) difficult subject of RNA and proteins, with a lot of focus on elements of abiogenesis (origin of life). For example, Gerald Joyce talked about his recently published work on self-replicating and evolving RNA. I read the paper, which was very technical, and so I was looking forward to the talk to get a better understanding of the experiment. Not much luck with that, and on top of that I didn't get to ask him about, what I think is, his very strange definition of life. He argues that his replicating RNA has many of the traits of life, but not two that makes it non-life. The list is
- Replication (yes)
- Heritability (yes)
- Mutation through recombination (yes)
- Selection (yes)
- Evolution of pre-existing function (yes)
- Replication contingent on other functions (yes)
- Capability for invention of novel function (no)
- Open-ended evolution (no)
However, the poster session was amazing. Michael Behe is here, and on his poster he argued from experiments with bacteria that, contrary to the observation that organisms increase in complexity (defined as number of promoters and genes), evolutionary theory predicts that it should decrease, because by far the most beneficial mutations result in loss of promoters and/or genes. I wholeheartedly disagree, because gene duplication, by his definition, increases complexity without having any effect on fitness (mostly). He countered that the rate of duplication is too low (1e-8 - 1e-9), but I don't see why that should be too low - it has to be compared to the rate of beneficial mutations, which is also very low (and perhaps comparable to that of gene duplications).
Another good poster was by Paul Bingham, Stony Brook, who argued that there is a causal correlation between human brain size and village size, as he put it. And the link... is throwing. Have you ever seen a chimp throw? It doesn't even throw like a girl. It simply isn't built for it. But humans are, and the advantages are clear: aggressive scavenging and low cost to ostracize. There is evidence of correlation from 1.8 million year old artifacts, but I was not alone about wishing for a testable hypothesis and some quantitative data.
Susan Lindquist from Cambridge, MA gave a an excellent talk in the evening on the influence of protein folding on evolutionary change. Chaperones (e.g. Hsp90) can facilities the evolution of new traits by three mechanisms, one of is by buffering the effect of small mutations, allowing the storage of cryptic genetic variation that is released by stress.
Check back tomorrow for words about Hopi Hoekstra (molecular phenotypic optima), Nick Barton (sex and recombination), Daniel Dennett (cultural evolution of words), and Matt Ridley also on some cultural evolution thing. And, the posters look even better again tomorrow. There's a great looking one on peaks in artificial fitness landscapes.
Here's a list of abstracts.