RESUMEN
Genetic structure of 11 pig breeds and lines of different origins and production specialization for 10 quantitative traits loci: RYR1, GH, IGF2, CTSL, CTSS, CTSB, CTSK, MC4R, ESR1 & PRLR was analyzed. The results allow us to suppose that the uniqueness of genetic structure of each breed is largely determined by features of the allelic structure of a number of loci. Breeds of different production specialization differ significantly for such QTL, as RYR1, MC4R, ESR1 and IGF2. However, we have found that the loci CTSB, CTSL, CTSK, CTSS and PRLR in most of investigated breeds showed similar distribution of alleles, significant genetic differentiation between breeds and within breeds for these loci is missing. The exception is the Large Black breed for the CTSB locus and Ukrainian steppe spotted breed for the CTSL locus. Also, it can be assumed that allelic structure of some of investigated loci are more connected with the origins of pig breeds than to the selection on production traits. This refers, for example, to the growth hormone gene, the using of which in marker assisted selection could be effective only in some populations. The genetic distance between breeds and lines was defined and the dendrogram of the genetic relationship was built. Breeds are grouped in connection with the production specialization, as well as by their origins.