Allele frequencies, numbers of alleles and observed heterozygosities (<i>H_O</i>) for the <i>Aime</i>-MHC class II beta genes.

*: P<0.05.
**: P<0.01.
Numbers in parentheses are the total numbers of alleles.
aThe alleles bolded were newly identified in the current study, while the others were defined in previous studies [30], [31];
band c indicate the allele was Sichuan subspecies-specific and XXL-specific (refuge), respectively.