Genetic distances between horse breeds in Poland estimated according to blood protein polymorphism

Abstract

ABSTRACT. The objective of the study was to estimate the heterozygosity and phylogenetic relationship between horse breeds in Poland, according to erythrocyte antigens and protein polymorphisms. The study included 15 434 horses: Polish Coldblood, Małopolski, Wielkopolski, Hucul, Polish Konik, Biłgorajski, Felin Pony, and ponies of Shetland origin. A total of 14 loci were studied: seven blood groups and seven protein polymorphism systems. Phylogenetic trees obtained for the erythrocyte antigens and protein variants were mostly alike which suggests that both kinds of markers may be equally used in estimating the similarity of animal populations. The lower polymorphism of the structural and enzymatic proteins, as compared with the erythrocyte antigen, resulted in a lower number of alleles per locus, lower heterozygosity, and closer genetic distances. The level of heterozygosity and phylogenetic trees of the breeds turned out to be mostly concordant with the known history of the populations. Małopolski and Wielkopolski horses are the most homozygous, the Huculs, Polish Koniks, and Biłgorajskis have a middle position, while the Polish Coldbloods and the ponies are the most heterozygous. The Polish Koniks are the most related to other breeds which shows that all the breeds studied, Polish Coldbloods included, have many indigenous ancestors. The Huculs, Polish Koniks, and Biłgorajskis are closely related. In spite of different histories, the Małopolski and Wielkopolski horses have the closest relationship. The Felin Ponies cluster together with the Shetlands. According to the blood groups and protein variation, the genetic diversity of the studied horse breeds is low and mainly due to individual differences. The low genetic variability of the breeds suggests reconsidering the long-term strategies of horse breeding in Poland, particularly of the conserved breeds.

Recognising the potential role of native ponies in conservation management

“…The largest genetic difference observed was that between the Carneddau and the Section A Welsh, with a Wright's Fst (Wright, 1965) measure of genetic distance 0.157 when all datasets were compared. This value is comparable to the difference seen between established horse breeds in studies in France (Leroy et al, 2009) and Poland (Stachurska et al, 2014). Whilst we continue to argue that genetic degrees of difference should not be a hard limit on what humans consider a 'breed', the Carneddau Pony is clearly a distinct population far older than the Welsh Section A. Interestingly, other close relationships are apparent between the 'upland' types, suggesting the possibility of a shared 'upland' signature linked to adaptation, though other factors such as common ancestry may be in play.…”

Inter- and intrabreed diversity of the major histocompatibility complex (MHC) in primitive and draft horse breeds

“…Furthermore, the pool of functional genes, such as MHC, even in domestic horses undergoing artificial selection, might still depend on environmental factors. A study by Stachurska et al [77] on genetic distances between common breeds in Poland estimated the Nei genetic distance between Konik polski and Polish draft horses based on erythrocyte antigen and protein loci as 0.04, which is less than any of the Nei's distances calculated between the populations used in the present study (0.07 to 0.71). When genetic clustering was applied, the differentiation between horses based on MHC microsatellite alleles decreased (0.04 to 0.6); however, the clusters were still more genetically distinct than when neutral markers were used in the calculation.…”

Inter- and intra-genetic diversity in the Polish Konik horse: implications for the conservation program

“…All of the lines are included in the currently realized conservation program. Over the last decades, comparative analyses of PK with other horse breeds have been reported by some authors (Stachurska et al 2004(Stachurska et al , 2014.…”