A1 Refereed original research article in a scientific journal
Genetic differentiation between the old and new types of Serbian Tsigai sheep
Authors: Cinkulov M, Tapio M, Ozerov M, Kiselyova T, Marzanov N, Pihler I, Olsaker I, Vegara M, Kantanen J
Publisher: EDP SCIENCES S A
Publication year: 2008
Journal:: Genetics Selection Evolution
Journal name in source: GENETICS SELECTION EVOLUTION
Journal acronym: GENET SEL EVOL
Volume: 40
Issue: 3
First page : 321
Last page: 331
Number of pages: 11
ISSN: 0999-193X
DOI: https://doi.org/10.1051/gse:2008006
Web address : http://www.gsejournal.org/content/40/3/321
Abstract
Two Tsigai sheep populations exist in Serbia: the Old type, called Cokan, and the New type. It is assumed that the New type results from upgrading Tsigai sheep with exotic genetic material. We investigated genetic diversity and di. fferentiation of these types by analysing 23 autosomal microsatellites. Tests for Hardy- Weinberg proportions, linkage equilibrium between genotypes across loci and the calculation of inbreeding coeffcients were performed and the deficiency in the number of alleles within the Tsigai types was examined using a Wilcoxon sign- rank test. The New type displayed a higher level of genetic variability than the Cokan in terms of allele numbers, but the New Tsigai showed a pattern of heterozygosity deficiency. The positive f value for the Cokan 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 i. e. the two Tsigai types are clearly di. erentiated and the New Tsigai type has been influenced by cross-breeding. Therefore, the Cokan Tsigai should be considered as a distinct endangered breed in the FAO classification.
Two Tsigai sheep populations exist in Serbia: the Old type, called Cokan, and the New type. It is assumed that the New type results from upgrading Tsigai sheep with exotic genetic material. We investigated genetic diversity and di. fferentiation of these types by analysing 23 autosomal microsatellites. Tests for Hardy- Weinberg proportions, linkage equilibrium between genotypes across loci and the calculation of inbreeding coeffcients were performed and the deficiency in the number of alleles within the Tsigai types was examined using a Wilcoxon sign- rank test. The New type displayed a higher level of genetic variability than the Cokan in terms of allele numbers, but the New Tsigai showed a pattern of heterozygosity deficiency. The positive f value for the Cokan 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 i. e. the two Tsigai types are clearly di. erentiated and the New Tsigai type has been influenced by cross-breeding. Therefore, the Cokan Tsigai should be considered as a distinct endangered breed in the FAO classification.
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