The genes of the black sheep

Several genes affecting the wool's colour in sheep are known. Two of these genes are examined in this project by reading the DNA letters of some Swedish sheep breeds. The two genes are ASIP and MC1R. We have at first chosen to study sheep with black, white or grey colour. The purpose is to identify which changes in the genes give black colour and grey. At the first stage we focused on finding the cause of black colour in Swedish sheep breeds. Grey has proved to be harder to explain so the work is still ongoing.

In both MC1R and ASIP, other researchers have found changes in DNA that can explain black colour in several breeds of sheep in other countries. In the MC1R gene there are two changes in DNA that give black colour even if the animal inherits only one of these from one of their parents (so-called dominant inheritance). In the ASIP gene there are also two different changes in DNA, but these must be inherited from both the ewe and the ram to get black colour (so-called recessive inheritance).

The changes in the MC1R gene that give black colour, we have among the Swedish breeds so far only found at Swedish Finewool sheep. There are also some Swedish Finewool sheep that are black due to changes in the ASIP gene. In Swedish Finewool sheep, black colour can thus be inherited either dominant or recessively, depending on the genes of the individual. Black colour of some of the other breeds we investigated can be explained by the two previously known variants in ASIP.