Genet. Sel. Evol. 40 (2008) 321-331
DOI: 10.1051/gse:2008006

Genetic differentiation between the Old and New types of Serbian Tsigai sheep

Mirjana Cinkulov¹, Miika Tapio², Mikhail Ozerov², Tatyana Kiselyova³, Nurbiy Marzanov⁴, Ivan Pihler¹, Ingrid Olsaker⁵, Mensur Vegara⁶ and Juha Kantanen<sup>2

1</sup>  Department of Animal Science, Faculty of Agriculture, University of Novi Sad, 21000 Novi Sad, Serbia
²  Biotechnology and Food Research, MTT Agrifood Research Finland, 31600 Jokioinen, Finland
³  All-Russian Research Institute of Animal Genetics and Breeding, Russian Academy of Agricultural Science, 189620 St Petersburg-Pushkin, Russia
⁴  All-Russian Research Institute of Animal Husbandry, Russian Academy of Agricultural Science, 142132 Dubrovitsy, Russia
⁵  Department of Basic Sciences and Aquatic Medicine, Norwegian School of Veterinary Science, PO Box 8146 Dep., 0033 Oslo, Norway
⁶  Noragric, Department of International Environment and Development Studies, Norwegian University of Life Sciences (UMB), P.O. Box 5003, 1432 Ås, Norway

(Received 23 July 2007; accepted 13 November 2007; published online 10 April 2008)

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 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 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 differentiated and the New Tsigai type has been influenced by crossbreeding. Therefore, the Cokan Tsigai should be considered as a distinct endangered breed in the FAO classification.

Key words: microsatellite / sheep / Tsigai

Correspondence and reprints: juha.kantanen@mtt.fi

© INRA, EDP Sciences 2008