Quantitative genetics: evolution of quantitative traits

Now that we know how offspring resemble their parents, it's relatively straightforward to figure out how natural selection will affect the evolution of quantitative traits. The basic idea is really straightforward.

  • Natural selection changes the mean phenotype of individuals who reproduce relative to the whole population. (We'll be thinking only about viability selection.) The difference between the two is the selection differential, S.
  • We can predict the phenotype of the offspring from the mid-parent value using the heritability, h2.
  • The response to selection, R, is given by R = h2S.
Although the basic idea is pretty straightforward, getting there is a little hairy, but we'll take it slow and we'll all get there together.

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