Phylogenetic trees of ZNF280B/ZNF280BY and ZNF280A/ZNF280AY gene families. A. ZNF280B/ZNF280BY tree. B. ZNF280A/ZNF280AY tree. The bovine ZNF280BY and ZNF280AY gene families are consistently clustered with their autosomal paralog on chromosome 17, supporting that these two gene families originated from the transposition of the autosomal gene block. The trees were built based on the Neighboring-joining method implemented in MEGA4 software . The trees are drawn to scale and the evolutionary distances were computed using the Maximum Composite Likelihood method. The bootstrap values (1000 replicates) are shown next to the branches . The filled triangle indicates the condensed branch for each of the gene families. Scale: bar = 0.05 unit of the number of base substitutions per site. HSA = Human; PTR = Chimpanzee; MMUL = Macaque; MMU = Mouse; RNO = Rat; CFA = Dog; ECA = Horse; SSC = Pig; ORA = Sheep; BTA = Cattle.