Question

A cross between population 1 and 2 results in the following distribution of phenotypes:

White eyed, long wings: 46.5%

Red eyed, short wings: 46.5%

White eyed, short wings: 3.5%

Red eyed, long wings: 3.5%                                       7% of the time there is a crossing over event

A cross between population 1 and 3 results in the following distribution of phenotypes:

White eyed, thin antennae: 47.5%

Red eyed, club antennae: 47.5%

White eyed, club antennae: 2.5%

Red eyed, thin antennae: 2.5%

A cross between population 1 and 4 results in the following distribution of phenotypes:

Long wings, thin antennae: 44%

Short wings, club antennae: 44%

Long wings, club antennae: 6%

Short wings, thin antennae: 6%

Using the information above, map the relative positions of the E, A, and W genes on the chromosome.  

Remember to include relative genetic distances.

Answer 1

E - Eye, W - Wings, A - Antennae

A cross between population 1 and 2 Eye and Wings
       [(3.5 + 3.5)/100]X 100 = 7 cM

A cross between population 1 and 3 Eye and Antennae
        [(2.5 + 2.5)/100]X 100 = 5 cM

A cross between population 1 and 3 Wings and Antennae
         [(6 + 6)/100]X 100 = 12 cM

       A----5cM---E-------7cM---W
       --------------12cM----------------