Mitochondrial DNA-based genetic evaluation of autochthonous cattle breeds in Croatia

Genetic diversity and phylogenetic relationship of three Croatian autochthonous cattle breeds was analyzed using a sequence of the mtDNA D-loop region. Among Busha, Istrian, and Slavonian Syrmian Podolian cattle 146 unrelated animals were tested. The sequencing of 780 base pairs of the mtDNA D-loop region revealed 39 polymorphic sites representing 28 different haplotypes. The highest numbers of haplotypes were observed in the Busha population and the lowest in the population of Slavonian Syrmian Podolian cattle, while the highest level of sequence diversity within a population was observed in the Istrian cattle. Our results indicate a high level of mtDNA diversity in the populations of Busha and Istrian cattle and a low level of preserved diversity in the population of Slavonian Syrmian Podolian cattle. The sequence analysis showed substantial subdivision between the breeds (F-ST = 0.1434), and a large fraction of variation within the breeds. Although the dominant haplotypes are classified as the T3 haplogroup, some of the haplotypes are classified as the rarer T2 and T5 haplogroups. Genetic information based on mtDNA typing has a great importance for the future conservation management and preservation of genetic diversity in autochthonous cattle breeds.