Assume that three pairs of alleles are found in Drosophila x

Assume that three pairs of alleles are found in Drosophila: x+ and x-, y+ and y-, and z+ and z-. As shown by the symbols, each non-wild-type allele is recessive to its wild-type allele. A cross between female heterozygous at these three loci and wild-type males yields progeny having the following genotypes:

x+ y+ z+ females 1010

x- y+ z- males 430

x+ y- z+ males 441

x- y- z- males 39

x+ y+ z- males 32

x+ y+ z+ males 30

x- y- z+ males 27

x+ y- z- male 1

x- y+ z+ male 0

What is the recombinant frequency between x and y?

What is the recombinant frequency between x and z? Decimal answer only.

What is the coefficient of coincidence? Decimal answer only.

Solution

Since the most frequent male gentoypes are xzy+ and x+z+y; the gene order of X chromosome of female fly is xzy+/x+z+y

b) The recombination frequency between x and z= 32+27+1/ 1000= 6% or 0.06
a) The recombination frequency between x and y=
recombination frequency of z and y= 39+30+1/1000 = 7%= 0.07
So, x-y= 0.06 + 0.07= 0.13
c) Coefficient of coincidence= 1/0.06x 0.07x 1000 = 0.238