Genetic Diversity And Paternal Origin Of Y-SNPs And Y-STRs In Chinese Cattle

Molecular genetic markers have been widely used in animal origin evolution and genetic diversity studies.Unlike mitochondrial and autosomal DNA,Y chromosome molecular genetic markers are paternally inherited and provide evidence of paternal origin.Single nucleotide polymorphisms(SNP)and microsatellite(STR)are two classic Y chromosomespecific molecular markers.With its vast territory and complex natural environment,China boasts rich cattle genetic resources.At present,the genetic diversity and paternal origin of Y chromosomes in Chinese cattle are mainly concentrated in Northern and Central group.Few of the Southern group cattle breeds/ population were studied.In order to explore the genetic diversity,population structure and paternal origins of Chinese cattle,we used PCR amplification,sequencing and bioinformatics methods to analyze the polymorphism of YSNPs(UTY19 and ZFY10)and Y-STRs(INRA189 and BM861)in 33 Chinese cattle breeds/populations,including 575 Chinese cattle males represent 23 cattle breeds/ populations collected in this study as well as 302 data published in previous study,together with Holstein(N=30)and Xianan(N=32)breeds as control.The results were as follows:(1)Chinese cattle have higher Y chromosome genetic diversity.Chinese cattle were dominated by taurine Y2(Northern group)and zebu Y3(Southern group)haplogroups.A small number of Y1 haplogroup detected in Chinese cattle may be the result of the introgression of exotic cattle,and the degree of genetic introgression has an increasing trend.(2)The results suggest that the Y-STR marker INRA189 cannot be used to distinguish Bos taurus or Bos indicus origin in Chinese cattle.(3)Based on the Y chromosome haplotypes,it is inferred that Tibetan cattle was a special group of cattle with abundant haplotypes.Tibetan cattle mainly originated from Bos taurus,but also influenced by zebu introgression.(4)By analyzing the similarities and differences between Y chromosome haplotypes of Chinese native cattle breeds/populations and foreign famous commercial cattle,this study revealed the potential of part of Chinese cattle breeds/populations to be cultivated in the direction of specialized beef cattle breeds.In this study,a comprehensive analysis of Y chromosome polymorphisms in Chinese cattle was conducted,which provided a theoretical basis for a better understanding of the genetic polymorphism and patrilineal origin of Chinese cattle breeds/populations.