Wild type

Wild type is a term in genetics for the most common type in a natural population. It is applied to alleles of a gene, or the genotypes or phenotypes of a species.
The term is used in genetics to contrast normal alleles with mutant alleles.
With "Drosophila melanogaster", wild type usually means the standard version of the famous laboratory population used in the T.H. Morgan laboratory, and since used around the world. This was, of course, only a small sample of the natural populations.
Actually, we propbably know more about "Drosophila pseudoobscura" in the wild than "Drosophila melanogaster", because of a huge series of studies done by Theodosius Dobzhansky and his colleagues after World War II.