Chapter 3, Problem 5P

In the fruit fly Drosophila melanogaster, very dark (ebony) body color is determined by the e allele. The e allele produces the normal wild-type, honey-

colored body. In heterozygotes for the two alleles (but not in e e homozygotes), a dark marking called the trident can be seen on the thorax, but otherwise the body is honey-colored. The e and e alleles are thus considered to be incompletely dominant.

a.	When female e+e+ flies are crossed to male e+e flies, what is the probability that progeny will have the dark trident marking?
b.	Animals with the trident marking mate among themselves. Of 300 progeny, how many would be expected to have a trident, how many ebony bodies, and how many honey-colored bodies?