Y chromosome genetic diversity and breed relationships in native Polish cattle assessed by microsatellite markers

Cattle provide a wide range of products and services to humans; thus the significance of conservation of livestock genetic resources is evident. We analyzed the genetic variability of five Y-chromosomal microsatellites in 395 bulls representing six cattle breeds (Polish Red, Polish Whitebacks, Polish Red-and-White, Polish Black-and-White, Polish Holstein Friesian, and Simmental). We identified three haplotypes in the paternal gene pool of analyzed populations. Haplotype diversity was low and frequencies ranged from 9.87% to 100%. In Polish autochthonous breeds (Polish Red, Polish Whitebacks), we detected two and three haplotypes. The network analysis revealed that tested bulls of both breeds were distributed in two clearly separated haplogroups. The dominant frequency in the Polish breeds had the haplotype also prevalent in the majority of European cattle. Only three Whitebacks carried a haplotype not identified until now in any international cattle breed. We showed that partitioning of genetic variation among breeds can be mainly explained by their assignment to past improvement crossings and reflected the low male effective population size. Our findings point also to a great importance of preservation of genetic diversity in indigenous cattle breeds.