Task- genetics
The genes for body color (A), eye color (B) and wing length (C)are linked to the same autosomal chromosome of D. melanogaster, inthe order of A - B - C. For body color, alleles encode 'A +' forwild type and 'a' for black body; for eye color, alleles encode 'B+' for wild type and 'b' for pink eyes; For wing length, allelescode 'C +' for wild type and 'c' for short wings. Wild-type alleles('A +', 'B +', 'C +') dominate the mutant alleles (a, b, c) and thegenetic distances between loci are determined at 10 cM (A-B) and 20cM (B - C).
A pure-eyed female with black body color, short wings andwild-type eyes is crossed to a male with pink eyes and wild-typephenotype for the two other characteristics of the parentgeneration. The F2 generation is created by crossing F1 females tomales from a strain expressing all three recessive mutantproperties (analysis crossing).
a) What is the expected frequency of double crossover among theF2 offspring?
b) What is the allelion in the F1 female (indicate as achromosome sketch)?
c) What phenotypes will be observed among the offspring in F2and in what conditions if the interference is 1?
d) What phenotypes will be observed among the offspring in F2and in what conditions if the interference is 0?
