Drosophila has four pairs of chromosomes the sex chromosomes

Drosophila has four pairs of chromosomes: the sex chromosomes (XX in the
females; XY in the males) and three pairs of autosomes. You are studying a new
mutant strain with blue eyes. You wish to know if blue eye colour is a dominant
mutation and on which chromosome the blue eye locus can be found. When you
cross a pure?breeding female blue?eyed fly with vestigial wings and spineless
bristles to a male fly with wild type eye colour, wings, and bristles, all of the F1
progeny are completely wild type. An F1 male is backcrossed to a triple mutant
female, producing the following progeny (remember that there is no crossing
over in Drosophila males):

Wild type eyes, wings, and bristles: 72 females, 69 males
Wild type eyes and bristles, vestigial: 83 females, 77 males
Wild type wings, blue eyes, spineless: 60 females, 65 males
Blue eyes, spineless, vestigial: 62 females, 58 males

a. Is the mutation dominant or recessive? Explain.

b. Since you know that the locus for vestigial wings is on chromosome 2 and the
locus for spineless bristles is on chromosome 3, what chromosome carries the
locus for blue eyes? Show your work, including the step?by?step reasoning
you used to arrive at your answer.

c. When an F1 female is backcrossed to a triple mutant male, the following 1,000
progeny are produced:
Wild type eyes, wings, and bristles: 90 females, 89 males
Wild type eyes and bristles, vestigial: 83 females, 98 males
Wild type eyes and wings, spineless: 37 females, 35 males
Wild type wings and bristles, blue
eyes: 36 females, 34 males
Wild type wings, blue eyes, spineless: 92 females, 88 males
Wild type eyes, spineless, vestigial: 34 females, 39 males
Wild type bristles, vestigial, blue eyes: 33 females, 37 males
Blue eyes, spineless, vestigial: 90 females, 85 males
Calculate the map distance between blue eye and any linked genes. Show
your work.

Solution

Hi,

Mutation is recessive Because it is clearly seen that number of wild type eye drosophila is more than the blue eyed.

And ratio also shown same.

That is why mutation is recessive.