2008 GCK problems (self-extracting zip file; installs to B:\ drive by default)

2008 GCK problems (generic zip archive)

Note: The GCK manual is also available online in pdf format.

Two weeks ago, we established Parental crosses that consisted of wild-type (wt +) male Drosophila and female flies that had white eyes (w), miniature wings (m), and forked bristles (f).

The phenotypes of this cross can be denoted:

The parental flies were allowed 7 days to mate and were then cleared from the vials to avoid any mating between parents and offspring. The offspring or progeny of the parental cross are called the F₁ or first filial generation.

After you have examined the flies and have attempted to figure out the genetic system of the three mutant traits, check your answer by clicking here.  

Don't cheat and look before you have tried to figure it out for yourself!!!

If you look closely, you should notice that all the F₁ male and female flies resemble those pictured below:

We can determine the genotypes of our parental flies based on the phenotypes of the F₁ flies. Since all of the F₁ males are triple mutants and all of the female are wt⁺ , we know that w, m and f must be sex-linked traits and are on the X chromosome. The parents of the F₁ were thus,

In the F1,

males are X^wmfY = wmf phenotypically. This shows that w, m, and f are recessive traits. Females are X⁺⁺⁺X^wmf= wt⁺ phenotypically.
 

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