Wild Type vs. Mutant

Wild Type vs. Mutant Traits

Most populations are polymorphic for most phenotypic traits, from fur color to blood type.

The allele that encodes the phenotype most common in a particular natural population is known as the wild type allele. It is often designated, in genetic shorthand, as "+".

Any form of that allele other than the wild type is known as a mutant form of that allele. Here are a few examples...

Wild type penguins wear tuxedos. Albino mutants look nekkid.

Wild type tigers have orange fur and black stripes. One mutation prevents the deposition of the orange/brown pigment, and the result is a "white tiger" that still has dark stripes. A different mutation prevents any melanin (brown pigment) from forming at all, and the result is an albino tiger.

The "black panther" is actually a mutant version of a leopard (or a jaguar) in which the yellow fur has dense deposits of melanin, making it black. The spots are still there, but harder to see. A black version of any wild type animal is said to be melanistic.

Wild type lagomorphs (rabbits, hares and pikas) and rodents usually have a fur color called agouti. The hair shafts are banded with black/brown/black.

But albino and melanistic forms also occur.