Homework Assignment #7

Questions

1. You have read in a Theoretical and Applied Genetics
1. manuscript that the authors reported a 100cM distance
1. between two loci.

a) Find 'p' which is the observed recombination
a) fraction between the two loci based on
a) two-point linkage analysis.

b) Explain why the estimate of p does not equal
b) the distance in centiMorgans.

2. You are planning an experiment to determine whether
2. the segregation of two unlinked loci which determine
2. the phenotype of a trait fits a 9:7 ratio or a 13:3 ratio.

a) What is the minimum number of F₂ progeny that
a) must be grown to distinguish between the two
a) ratios when the probability of Type I error is
a) set at 0.05?

b) What is the critical number of dominant
b) phenotypes that are necessary to distinguish
b) between these two ratios when a = 0.05?

3. A trait is determined by two loci located on
3. non-homologous chromosomes. You want to determine
3. whether a parental plant is homozygous dominant
3. (AABB) or doubly heterozygous (AaBb). The parental
3. plant is self-fertilized to produce the F₂ generation.
3. The expected F₂ ratio of an AaBb plant is 15 purple
3. flowered plants: 1 white flowered plant. How many
3. F plants must be grown to determine correctly in 99
3. out of 100 trials whether the parent plant is doubly
3. heterozygous?

4. Plot the information content, as the recombination
4. fraction (p) is varied, for two loci in coupling phases
4. linkage using F₂ data.