Sometimes a speaker is so fascinating all you want to do is listen to them for hours.
I was left with this impression after attending the keynote lecture at the Eschaton 2012 conference, which was held in downtown Ottawa from November 30 to December 2.
Like many people, my understanding of evolution is based on a basic view of natural selection.
The child’s version goes something like this: If a specific trait gives a distinct advantage to a person, and that individual reproduces offspring, and this offspring in turn reproduces, then this powerful trait will spread in a population.
With his unique humour, Prof. Myers pointed to the comic book character Wolverine as a fictitious example. A simple view of evolution would state that Wolverine’s extraordinary powers give him a definitive advantage, and that natural selection would spread this trait among his offspring and, eventually, the population at large.
There is only one problem with this explanation: sex.
“Sex is weird not only because of what people do, but it is also weird genetically,” explained Prof. Myers.
To make this point, the roughly 200 attendees were told that human beings are like creatures made of Lego. When an individual reproduces, their genetic Lego parts are disassembled, and then half of their pieces are mixed up with somebody else’s, with the offspring containing a new, mixed-up collection of Lego parts.
Returning to Wolverine, his superpower genes may or may not be passed on to his offspring. This is where chance comes in.
“(Sex) randomizes the collection of genes,” Prof. Myers told Apartment613 after the talk when asked for further clarification.
So why does sex scramble genes in offspring? One explanation is that sexual reproduction protects offspring from receiving bad genes, replied Prof. Myers. In other words, if a parent has a deleterious gene, but their offspring only have a 50 per cent of receiving it, then future generations can be partially protected. The negative consequence of this process is that positive genes may also be lost through sexual reproduction.
So what role does chance play in evolution?
“Selection works with large populations with low mutation rates,” Prof. Myers noted in his talk. “Small populations with a high mutation rate are dominated by chance.”
The lecture went on to discuss other ways in which a mutation can take hold in a population, such as the founder effect, genetic draft / hitchhiking, and random drift.
It would be disingenuous of me to pretend that I am an expert in the evolutionary process, or that I can properly explain other ways in which chance impacts evolution. I will therefore let others explain these ideas. (See here and here as a starting point; you can read Prof. Myers’ blog here). However, I would like to flag this fascinating talk, and hopefully inspire others to study this area, for I know that my curiosity is peaked.
In the meantime, I should note that Prof. Myers used a hilarious slide in his PowerPoint presentation of Lego figurines having sex while making his point. Who said scientists can’t have fun?