Mitochondrial control region diversity in Polish sheep breeds

Abstract

Abstract. The aim of the study was to determine the genetic variability of the Polish sheep breedsŚwiniarka, Wrzosówka, Pomorska, and Wielkopolska based on mitochondrial control region polymorphism. A comprehensive phylogenetic analysis and information about the genetic origin of the breeds were also obtained. The genetic variability of the breeds studied has been assessed based on the number of haplotypes, haplotype diversity, nucleotide diversity, the average number of nucleotide differences, the number of mutations, and phylogenetically informative sites. Sequence divergence between identified haplogroup A (HA) and haplogroup B (HB) was also calculated. Moreover, a neighbour-joining (NJ) haplotype tree was constructed based on Kimura's two-parameter genetic distance calculation. Finally, the history of the population was investigated by mismatch distribution and Fu's F statistics. The 559 bp long mitochondrial DNA (mtDNA) control region (CR) sequences of 143 sheep were analysed. The 65 haplotypes were defined by 45 parsimony informative sites. Among the four Polish breeds, Wrzosówka had the highest whileŚwiniarka the lowest values of haplotype (H d ) and sequence diversity (π ) (H d = 0.9735 and π = 0.0040 for Wrzosówka; H d = 0.8975 and π = 0.0030 forŚwiniarka). Five haplotypes were shared between breeds, whereas the remaining 60 were unique. The NJ phylogenetic tree has revealed that 61 haplotypes of all analysed breeds clustered into clade B while the remaining 4 haplotypes representing all but theŚwiniarka breed pooled together with clade A. None of the other reported mitochondrial haplogroups were identified. The haplotypes representing HB formed a star-like network with the single central haplotype, which in association with extensive haplotype sharing reveals a weak structure of Polish breeds and the existence of gene flow between the breeds studied.

The genetic profiles and maternal origin of local sheep breeds on Java Island (Indonesia) based on complete mitochondrial DNA D-loop sequences

“…A comparison of the number of individual samples and the number of haplotypes ( Table-2 ) indicated that each breed had its haplotypes that could be due to the high diversity in local sheep breeds on Java Island and/or sampling strategy (collecting unrelated individuals) [ 31 ]. This is in line with the previous studies which states that several sheep breeds in Indonesia have high genetic diversity within [ 39 ] and between [ 50 ] populations. Unique patterns in the distribution of haplotypes could be attributed to the total reproductive isolation because of the harsh geographical structure of and unique husbandry practice on Java Island, that allow farmers to select animals with unique phenotypic characters associated with the adaptability to different ecological conditions [ 51 , 52 ].…”

“…[ 53 ] that Indonesian sheep have two Hap, namely, Hap A and B. Hap A is mainly represented in Asian breeds, whereas Hap B is found in high frequencies in European breeds [ 54 , 55 ]. This study is similar to observations on four Polish sheep breeds [ 39 ], eastern Ethiopia sheep [ 47 ], and Kail sheep [ 56 ] that form two Hap, namely, Hap A and B. All JFT, JTT, BTR, and WSB sheep are classified as Hap B.…”

“…The HD value and the average number of pairwise differences (K) within all tested breeds were 0.99567 and 25.36364, respectively. The HD value in this study is almost the same as fat-rumped sheep in Ethiopia (0.99) [ 47 ], five Egyptian sheep breeds (0.968) [ 37 ], four Polish sheep breeds (0.9720) [ 39 ], Savak Akkaraman sheep (0.995) [ 48 ], Iranian indigenous sheep (0.996) [ 31 ], Karayaka sheep (0.998) [ 33 ], and Mongolian native sheep (0.93) [ 3 ]. The K value in this study is similar to 10 Iranian indigenous sheep breeds (25.23) [ 31 ], but higher than five Egyptian sheep breeds (17.14782) [ 37 ], Romanian Racka sheep (6.70488) [ 49 ], and Savak Akkaraman sheep (7.068) [ 48 ].…”

“…The difference in the results might be due to the research methods, including the analysis methods, sample location, and the number of samples [ 36 , 37 ]. High genetic diversity in these results might be influenced by increased mutation rates in the mtDNA D-loop, the maternal effect of multiple wild ancestors, crossbreeding, and intercrossing in agricultural practices, the mixing of populations from different geographical locations, overlapping generations, natural selection, and genetic drift [ 36 , 38 , 39 ].…”

Genetic Characterization of Kazakh Native Sheep Breeds Using Mitochondrial DNA

“…Studies of many scientists on sheep from the Egyptian and Italian sheep breeds (Othman et al, 2015), Iranian sheep (Rafia and Tarang, 2016), Polish sheep (Koseniuk and Slota, 2016), Nepalese sheep (Gorkhali et al, 2015) were presented. The fragment of the D-loop region used in these studies varied from 76 to 721 b.p., with 55-132 polymorphic sites.…”