Over the past month or so I’ve been blogging chapter 5 of Evolutionary Genetics: Concepts & Case Studies. This chapter covers “stochastics processes,” basically the random elements in the flux of gene frequencies in biological populations. Now, I’m a selection man for real, but to understand selection you need to put it into the context of evolutionary dynamics as a whole, and chance is essential to properly comprehending necessity.
First I covered the immediate danger of extinction for a new mutant allele, even those favored positive selection’s kiss. Then I traced out the possibilities which influence the transition out of the boundary of emergence. Next I cruised into the familiar paths of genetic drift. Now I will hit genetic draft. Like Iran vs. Iraq there is only a one letter difference here between draft & drift, and in some ways the two processes do mirror each other, but the ultimate take home lesson is that it is in their differences that the solutions to biological problems may lay. Before you go on, I highly suggest you read Robert Skipper’s comments on this topic, his two blog posts on the topic, as well as this paper. If you read them first you don’t really need to read the rest of this if you understand them well enough. Also, since Rob has outlined John Gillespie’s mathematics in nearly exact detail I won’t explore that as much as I would have, and simply refer you to his paper if you can’t get a copy of Evolutionary Genetics: Concepts & Case Studies and don’t have access to the original papers via academic journal access. Much of the formalism mimics aspects of the genetic drift post in any case.