1. In Drosophila, the mutant genes for ebony body andpeach eyes, e and pe respectively, are linked. A female fly with normal eyes and body colour is mated to a male homozygous recessive for both mutants. The following progeny phenotypes were obtained:

e, Pe 33 E, Pe 12 e, pe 18 E, pe 27

a) Write the genotypes of the parents. Were the mutants in cis or trans in the female parent? The un-recombined chromosomes are said to be parental types, which are the most frequently occurring and the others, the two least frequent progeny are said to be the recombinant.

b) Write the genotypes of the offspring. Which are recombinant?

c) How may map units separate e and pe? To calculate the map units separating the genes, count the number of recombinant offspring and express this figure as a percentage of the total progeny.