In 1298 Marco Polo reported seeing chickens that "have hair like cats, are black and lay the best of eggs" -- an apt description of Chinese Silkies, the most popular black-skinned chicken breed. But black skinned breeds are also found in India, Indonesia, Japan, Korea, Sweden and Vietnam.
What does this all mean? Setting aside the concept of survival of the fittest in nature, it seems clear that people select for whatever traits intrigue them.
The researchers concluded: We have examined four different chicken breeds from both Asia and Europe displaying dermal hyperpigmentation and conclude that the same structural variant underlies this phenotype in all chicken breeds. This complex genomic rearrangement causing a specific monogenic trait in the chicken illustrates how novel mutations with major phenotypic effects have been reused during breed formation in domestic animals.
In other words, they believe all domesticated black-skinned chickens result from the same DNA coding anomaly and they probably suspect that all black-skinned breeds are derived from a single ancestor.
|Chinese Silkie chick shows black skin|
Photo by Jennifer F.