Question

In Drosophila melanogaster, the recessive allele for the sepia locus (se) causes flies to have very dark colored eyes. The recessive allele at the apterous (ap) locus causes the fly to lack wings.
A male from a true breeding line of sepia eyed, apterous flies (line A) is crossed to a female from a true breeding line of red eyed, winged flies (the "wild type" line B) to create an Fl:


Next, a female from the Fl is crossed to a male from line A.


The phenotypes of 1000 progeny from this test cross were scored as follows:


Eyes Body Number Observed


Red Normal 247

Sepia Normal 253

Red Apterous 251

Sepia Apterous 249 5.


What was the genotype of the F1?


A) SE se EB eb

B) se AP

c) se ap

D) SE se AP ap

E) Can't tell because of linkage

Answer 1

The answer will be E