Question

Describe the mechanisms by which meiosis would introduce genetic variability in a population. If one diploid yeast cell was heterozygous for an allele with a Dominant mutation on it, what proportion of its offspring could be expected to carry that dominant mutation after mating? (Assume it mates with a cell that is homozygous for the normal, recessive allele.)

Interestingly, yeast switch to sexual reproduction when they are under conditions of stress.

For the purposes of this task, assume yeast populations follow this simplified rule: When yeast are reproducing sexually, they will be found as diploid cells that can go through meiosis (or mitosis), while populations that are producing asexually will include only haploid cells undergoing mitosis. Remember that chromosomes can be counted using karyotypes

Answer 1

Explanation:- During Meiosis-I at Prophase-I of pachytene stage crossing over or recombination occurs between two non sister chromatids of homologous chromosomes resulting in exchange or reshuffling of genes. This process is universal among sexually reproducing organisms and is responsible for all types germinal variations that are passed on from parents to offsprings. 50% of offsprings would be carrying dominant mutation when the heterozygous is crossed with homozygous recessive. For example Aa x aa the result will be Aa, Aa, aa, aa 1:1 ratio