Cattle.

Bos taurus

Coat color is controlled by MC1R Extension (E^D dominant black > e recessive red, with breed-specific additional alleles), with PMEL17/SILV dilution acting on top to produce the cream of Charolais and the gray of Highland and Simmental dilute. POLLED is autosomal dominant on BTA1 with at least four geographically distinct mutations (Celtic, Friesian, Mongolian, Guarani). Belgian Blue and Piedmontese carry breed-defining MSTN myostatin mutations producing double muscling (Grobet 1997 PNAS). Multiple breeds carry well-characterized lethal recessive disorders with industry DNA tests: Holstein has BLAD, DUMPS, CVM, and lethal haplotypes HH1 through HH7; Jersey has JH1 (CWC15); Angus has AM (curly calf), NH (neuropathic hydrocephalus), and CA (contractural arachnodactyly); Dexter has the lethal homozygous bulldog chondrodysplasia at ACAN.