Polymorphism Of ELA-DQA In The Endangered Przewalskii’s Horse(Equus Przewalskii) In China

Major histocompatibility complex (MHC) genes are the most polymorphic in vertebrates and its expressions play a crucial role in pathogen recognition. Przewalskii’s horse is the only true wild horse, a species that has been extinct in the wild and all the current living individuals descend from12founders a species. The MHC class Ⅱ locus DQA polymorphism was analysed in a sample of31Przewalskii’s horses, that from two captured populations that propagated in Xin jiang and Gangsu province of China, using PCR-SSCP genotyping and DNA sequencing techniques. The main results are as follows:(1) This study proved" CTAB+gel purification" non-invasion research technique can be carried on Przewalskii’s horse’s MHC genetic diversity detection;(2)7ELA-DQA*exon2allele were found in this study and4of which are new ones.Our experiment proved that Xinjiang wild horse populations’s genetic diversity at DQA loci is higher than Gansu wild horse populations.(3) ELA-DQA3and ELA-DQA4were the dominant allele of Xinjiang Przewalski horse populations and ELA-DQA2、 ELA-DQA6were the rare allele in this populations. Gansu population with ELA-DQA1as dominant allele, ELA-DQA5and ELA-DQA7were rare in the populations.(4) Both of Xinjiang and Gansu Przewalski horse populations departure from Hardy-Weinberg equilibrium.(5) The nucleotide genetic distance of the7ELA-DQA*exon2alleles is between0.012and0.161Poisson corrected amino acid genetic distance of the founded alleles is0.01-0.334, indicates that Przewalski horse’s MHC gene with high variability.(6) Phylogenetic analysis of Przewalskii’s horse and other equid’s DQA sequences demonstrated Przewalski horse and donkey with domestic horse have a close relationship.