Why amorphic alleles are usually recessive to wild-type alleles?

What are Hypermorphic alleles?

What are Hypomorphic alleles?

In the fruit fly, dumpy wings (d) and purple eyes (p) are encoded by mutant alleles that are recessive to those that produce wild type traits; long wings (d+) and red eyes (p+). These two genes are on the same chromosome. In a particular lab, two researchers Walt and Jesse crossed a fly homozygous for dumpy wings and purple eyes with a fly homozygous for the wild type traits. The F1 progeny, which had long wings and red eyes, was then crossed with flies that had dumpy wings and purple eyes. Unfortunately, the progeny of this cross somehow escaped. To prevent their other projects from contamination, they decided to spend an exceptionally boring hour in the lab catching and counting the progeny and found the following:   long wings, red eyes – 482 dumpy wings, purple eyes – 473 long wings, purple eyes – 23 dumpy wings, red eyes - 22   What is the genetic distance between these two loci? a. 4.5 cM b. 55 cM c. 45 cM d. 49.5 cM  e. 4.7 cM