Genetic differentiation between the Old and New types of <it>Serbian Tsigai </it>sheep
2008
Vegara Mensur | Olsaker Ingrid | Pihler Ivan | Marzanov Nurbiy | Kiselyova Tatyana | Ozerov Mikhail | Tapio Miika | Ćinkulov Mirjana | Kantanen Juha
<p>Abstract</p> <p>Two <it>Tsigai </it>sheep populations exist in Serbia: the Old type, called <it>Čokan</it>, and the New type. It is assumed that the New type results from upgrading <it>Tsigai </it>sheep with exotic genetic material. We investigated genetic diversity and differentiation of these types by analysing 23 autosomal microsatellites. Tests for Hardy-Weinberg proportions, linkage equilibrium between genotypes across loci and the calculation of inbreeding coefficients were performed and the deficiency in the number of alleles within the <it>Tsigai </it>types was examined using a Wilcoxon sign-rank test. The New type displayed a higher level of genetic variability than the <it>Čokan </it>in terms of allele numbers, but the New <it>Tsigai </it>showed a pattern of heterozygosity deficiency. The positive <it>f </it>value for the <it>Čokan </it>suggests the occurrence of inbreeding in this type. The proportion of linkage disequilibrium was below that expected by chance. Exclusion of two loci in Hardy-Weinberg disequilibrium did not alter our conclusions based on the entire data set <it>i.e. </it>the two <it>Tsigai </it>types are clearly differentiated and the New <it>Tsigai </it>type has been influenced by crossbreeding. Therefore, the <it>Čokan Tsigai </it>should be considered as a distinct endangered breed in the FAO classification.</p>
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