Question

1. When Mendel crossed long and short stemmed plants, all of the resulting F₁ plants had long stems. The the F1's were selfed. Assume that a single long-stemmed F2 plant was allowed to self. What is the probability that Mendel observed ONLY (O N L Y and nothing else at the same time) long-stemmed plants among the resulting F3 progeny?  

2. Consider a plant species with n=2. While studying a female flower, a cytogeneticist observes a particular meiocyte in which each pair of homologs is (transiently) connected by a single chiasma. Assuming meiosis, etc. proceed as normal, what is the probability that both chromosomes in the resulting spore will be recombinant?

3. Consider a Mendelian “pentahybrid”: Aa Bb Cc Dd Ee

How many different PHENOTYPIC classes would you expect to find among the progeny of the self-cross?

Answer 1

1)

3) The phenotypic ratio of pentahybrid cross will be

243:81:81:81:81 :81:27:27:27:27:9:9:9:3:3:1 .

Each of the ratio value depict a respective phenotypic class therefore 16 phenotypic classes can be expect to find among the progeny of the self crossed.