Mutation Selection Balance

Question 1

What is Fischer’s fundamental theorem and what does it imply about how selection and heritability determine fitness?

Answer 1

Fischer’s fundamental theorem is that the rate of increase of fitness in a population is equal to the additive genetic variance in fitness. It implies that selection will remove heritable variation in fitness.

Question 2

How did Fischer define fitness

Answer 2

As the lifetime reproductive success of a particular genotype

Question 3

Considering R=h^2S and the implications of Fischer’s fundamental theory, why would there be diversity?

Answer 3

1) Diversity is irrelevant to selection
2) Diversity isn’t heritable
3) Diversity is maintained by mutation
4) Selection sometimes favours diversity

Question 4

Describe the selectionist - neutralist debate

Answer 4

Selectionists thought variation in populations is maintained by selection. Neutralists thought variation is populations is eliminated by selection and therefore any variation in nature is selectively neutral or actively being eliminated

Question 5

Are there possible scenarios where mutations alone can account for the variation in a population? How likely is this?

Answer 5

Yes iff:
- there are many genes that affect the trait and selection is weak.

This is unlikely bc traits with many genes affecting them are probably important and important traits tend to have high selection intensity