Figure 3

PRNP polymorphism frequencies in U.S. cattle populations. PRNP polymorphism frequencies are shown for populations of Bos taurus (n = 94), Holstein (n = 86), Composite of U.S. Brahman (n = 20), British (n = 39), and Continental (n = 51). Hatched bars represent the proportion of polymorphisms where the minor allele was observed in only one animal (singleton). Polymorphism numbers are shown above the bars.