In Drosophila, the map distance between the Xlinked genes for white eyes (w, rec
ID: 50304 • Letter: I
Question
In Drosophila, the map distance between the Xlinked genes for white eyes (w, recessive to wild type red eyes) and miniature wings (m, recessive to wild type long wings) is 34.6 map units.
If a female fly heterozygous at both loci is crossed to a whiteeyed, miniaturewinged male and interference is complete, what proportion of the resulting progeny are predicted to be wild type if:
a. The dominant alleles are in repulsion in the heterozygous parent? Show your work.
b. The dominant alleles are in coupling in the heterozygous parent? Show your work.
Explanation / Answer
white eyes and miniature wings (wm/wm) * wild-type male (red eyes and large wings) (w + m + /Y)
F 1 males: white-eyed , miniature wings (wm/Y)
F1 females : wild-type for both the eye colour and wing size (w + m + /wm)
F2 from self cross of F1=
most frequent phenotypic classes both sex: white eyes, miniature wings and wild-type (red eyes, large wings)
fraction of wild type= cis configuration w + m + /wm ; trans configuration w + m/wm +
will be 0.63 or 243