There are four paris of chromosomes in Drosophila: the sexchromosomes (XX in females and XY in males) and three pairs ofautosomes. You are studying a new mutant strain with greeneyes. You want to know if green eye color is a dominantmutation and on which chromosome the green eye locus can befound. When you cross a pure-breeding female green-eyed flywith vestigial wings, and spineless bristles to a male fly withwildtype eye color, wings, and bristles, the F1 progeny all arewildtype. An F1 male is backcrossed to a triple mutantfemale, producing the following progeny:
wildtype eyes, wings, and bristles —– 73 females, 70 males
wildtype eyes and bristles, vestigial —– 84 females, 78males
wildtype wings, green eyes, spineless —– 53 females, 44males
green eyes, spineless, vestigial —– 63 females, 58 males
a. Is the mutation dominant or recessive? Explain.
I would say the green eye mutation is recessive because all the F1progeny yielded wildtype.
b. Since you know that the locus for vestigial wings is onchromosome 2 and the locus for spineless bristles is on chromosome3, what chromosome carries the locus for green eyes? Showwork including the step by step reasoning used to arrive to youranswer.