A Drosophila geneticist made a cross between females homozygous for three X-linked recessive mutations (y, yellow body; ec, echinus eye shape; w, white eye color) and wild-type males. He then mated the F1 females to triply mutant males and obtained the following results:

Determine the order of the three loci y, ec, and w, and estimate the distances between them on the linkage map of the X chromosome.

Transcribed Image Text:

Females Males Number ++ + /v ec w +++ 475 y ec w/y ec w y ec w469 y ++/y ec w y++ + ec w/y ec w + ec w7 y + w/y ec w y + w 18 + ec + /y ec w 23 +ec + ++ w/y ec w ++ w y ec + /y ec w y ec + 0