Question

Drosophila has four pairs of chromosomes: the sexchromosomes (XX in the females; XY in the males) and three pairs ofautosomes. You are studying a new mutant strain with blue eyes. Youwish to know if blue eye colour is a dominant mutation and on whichchromosome the blue eye locus can be found. When you crossa pure‐breeding female blue‐eyed fly with vestigial wings andspineless bristles to a male fly with wild type eye colour, wings,and bristles, all of the F1 progeny are completely wild type. An F1male is backcrossed to a triple mutant female, producing thefollowing progeny (remember that there is no crossing over inDrosophila males):

Wild type eyes, wings, andbristles: 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, 58males

Is the mutation dominant or recessive?Explain.

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 blue eyes? Showyour work, including the step‐by‐step reasoning you used to arriveat your answer.

When an F1 female is backcrossed to a triple mutant male, thefollowing 1,000 progeny are produced:

Wild type eyes, wings, andbristles: 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, blueeyes: 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, blueeyes: 33 females, 37 males

Blue eyes, spineless,vestigial: 90 females, 85 males

Calculate the map distance betweenblue eye and any linked genes. Show your work