Promoter methylation statues of Bvh gene in testis of cattle, yak and cattle-yak hybrid. A. BSP sequence and distribution of CpG sites in Bvh promoter of cattle, yak and cattle-yak hybrid. Underline means CpG site. Arrow means primers for BSP. Dashed line indicate core promoter. Nucleotide numbering is relative to +1 at the initiating ATG codon. B. The genomic organization of the cattle Bvh gene. Numbered vertical lines indicate exons. Hatched boxes indicate BSP-amplyfied region. C. The CpG sites of BSP-amplified region. Vertical lines indicate 20 CpG site. D. Bisulfite sequencing results for cattle, yak and cattle-yak hybrid. Each line represents an individual bacterial clone which was sequenced. Black dots indicate methylated CpG sites, open circles indicate unmethylated CpG sites.