suppose that a geneticist discovers a new mutation in drosophila melanogaster that causes the flies to shake and quiver. she calls this mutation quiver, qu, and determines that it is due to an autosomal recessive gene. she wants to determine whether the gene encoding quiver is linked to the recessive gene for vestigial wings, vg. she crosses a fly homozygous for quiver and vestigial traits with a fly homozygous for the wild-type traits, and then uses the resulting f1 females in a testcross. she obtains the flies from this testcross.
