Question

The genes A/a and B/b are 20 cM apart. In a cross AB/ab x ab/ab, which genotypes do you expect in the offspring, and with which frequencies? What are the expected gamete frequencies for an AB/ab individual? For an Ab/aB individual?

Answer 1

Answer:

AB/ab x ab/ab ---Parents

Distance between genes (cM) = Recombination frequency (%)

AB/ab genotype produces 4 types of gametes as below:

Recombinant gametes (20%):

Ab = 10%

aB = 10%

Non-recombinant gametes (80%):

AB = 40%

ab = 40%

ab/ab genotype produces only one type of gametes, ab.

	ab
AB (40%)	AB/ab (40%)
Ab (10%)	Ab/ab (10%)
aB (10%)	aB/ab (10%)
ab (40%)	ab/ab (40%)