QUESTION 6 a) Using the progeny data from a dihybrid testcross given in the tabl

ID: 276420 • Letter: Q

Question

QUESTION 6 a) Using the progeny data from a dihybrid testcross given in the table below, work out the genetic map distance between genes A and B. Show your work (2 marks) Genotype class Number of progeny AaBb Aabb aaBb aabb 108 235 262 123 b) State the genotypes of the parents of the dihybrid testcross shown above and draw the arrangement of alleles on the sister chromatids and homologues for each of the parents as they would be seen in prophase I of meiosis: (6 marks) Parent 1 Parent 2 Genotype: Arrangemert of alleles:

Explanation / Answer

Answer:

a).

Hint: Always recombinant progeny are smaller in number when compares to non-recombinant progeny. So that recombinant genotypes are AaBb & aabb.

Recombination frequency = (number of recombinant progeny / Total progeny)100

RF = (108+123/ 728)100 = 31.73%.

RF(%) = Map distance (m.u)

So the distance between the two genes, A & B = 31.73 mu..

b).

Parent 1

Parent 2

Genotype

AaBb

aabb

Arrangement of alleles

AB/ab

ab/ab