Chapter 5, Problem 19P

In Drosophila, the autosomal recessive dp allele of the dumpy gene produces short, curved wings, while the autosomal recessive allele bw of the brown gene causes brown eyes. In a testcross using females heterozygous for both of these genes, the following results were obtained: wild-type wings, wild-type eyes 178 wild-type wings, brown eyes 185 dumpy wings, wild-type eyes 172 dumpy wings, brown eyes 181

In a testcross using males heterozygous for both of these genes, a different set of results was obtained: wild-type wings, wild-type eyes 247 dumpy wings, brown eyes 242

a.	What can you conclude from the first testcross?
b.	What can you conclude from the second testcross?
c.	How can you reconcile the data shown in parts (a) and (b)? Can you exploit the difference between these two sets of data to devise a general test for synteny in Drosophila?
d.	The genetic distance between dumpy and brown is 91.5 m.u. How could this value be measured?