Characteristics of the Romanov Breed by the BMP-15 Locus Responsible for Prolificacy in Sheep

Resumo

The actual problem in identifying a prolificacy gene in Romanov breed sheep is considered. The new diagnostic method to identify the polymorphic gene of the bone morphogenetic protein 15 (BMP-15) influencing prolificacy in the Romanov sheep has been proposed based on the surveys. The frequencies of occurrence of the normal (wild-type) and mutant alleles and the genotypes present at a locus responsible for prolificacy in sheep are revealed. The quantitative indicators, including the numbers of lambs at birth and at weaning and the barren and culled ewes, were recorded with taking into consideration the genotypes at the BMP-15 locus. The correlation between the frequency of occurrence and the number of the produced posterity and among the barren and culled Romanov ewes were ascertained. It was indicated that the highest percentage of the lamb output at birth and at weaning was typical for the ewes homozygous (MM) for a mutant allele. The animals referred to as heterozygous genotypes (WM) appeared in the second position. The highest percentage of the culled and barren ewes was recorded in the carriers of the WW homozygote. Based on the obtained results, it has been concluded that the genotypes at the BMP15 locus should be taken into consideration when selecting the ewes with regard to their fertility. However, further researches into the determined phenomenon in the Romanov sheep are required to improve this performance, since multifetal pregnancies in some WW-group ewes have been registered.