The median-joining network (a) and geographic distribution (b) of the Zp2 coding haplotypes. Numbering of mutations follows the full coding sequence of the bovine Zp2 gene (from base 1 to 2142). Nonsynonymous mutations are shown in bold and italic. The size of each circle is proportional to its frequency in numbers of chromosomes. The haplotypes Zp2cdh7 and Zp2cdh8 from the outgroup species are not shown in the geographic map.
Chen et al. BMC Evolutionary Biology 2011 11:24 doi:10.1186/1471-2148-11-24