3. a. What determines the reproductive fitness of a genotype in a population? b.

Question

  3. a. What determines the reproductive fitness of a genotype in a population?

      b. If the absolute fitnesses of genotypes in our rodent population are 3 for TT, 4 for Tt and 6 for tt, determine the relative fitness of each genotype.

      c. Selection will occur on a locus when different genotypes result in different phenotypes that differ in reproductive fitness. What type of selection is occurring at the T locus (i.e. on the T and t alleles) in our population? Based on this information alone, what would you expect will happen to the f(T) and f(t) over time and why?

4. a. Define Genetic Drift at a locus. What assumption of the H-W equilibrium model is violated for genetic drift to occur?

      b. Why is the effect of genetic drift relatively "strong" (i.e. can cause larger change in allele frequency from generation to generation) in small populations and relatively "weak" in large populations? Include the following terms in your answer: gene pool, gametes, sampling error.

Explanation / Answer

4. a.

Genetic drift is the fluctuations in allele frequencies in gametes from generation to generation that occurs by chance. The phenomenon of genetic drift is characteristic of all populations.

The changes in allele frequencies that cause genetic drift occur randomly and are generally unpredictable. Genetic drift changes are found to be more accelerated if the population size moves towards reduction in size or shrink. Alteration of allele frequencies by random sampling of gametes is characteristic of genetic drift to occur, so H-W equilibrium model is violated (Allele frequencies should not be changed to obey H-W equilibrium.

(b) The alleles of all genes in a biological population are known as

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