A gene duplication affecting expression of the ovine ASIP gene is responsible for white and black sheep

Allele-specific expression of ASIP transcripts in nine white Merino sheep. Autoradiographs of PCR products from gDNA and cDNA from the skin of nine white sheep are shown. The size difference between the 189 (226)- and 184 (221)-, and the 189 (226)- and 180 (217)-bp fragments is due to the corresponding D₅ and D₉ deletions in the latter fragments. Seven sheep had both the N₉N₅ and N₉D₅ alleles. In one sheep (lane 5) all three alleles N₉N₅, N₉D₅, and D₉N₅ were present_. One sheep had only the nondeleted N₉N₅ alleles (lane 6). The nine white animals showed allele-specific expression of the functional N₉N₅ and D₉N₅ alleles. Expression of the nonfunctional N₉D₅ allele (arrow) was not detected. The different band intensities in the gDNA autoradiograph likely reflect the different allele copy numbers present in each animal.