POLYMORPHISM OF THE GROWTH HORMONE (GH) GENE IN SHEEP OF DIFFERENT BREEDS IN THE SOUTH OF RUSSIA

Abstract

The development of animal genetics and selective breeding has contributed
to the spread of the use of molecular markers in sheep farming in order to improve economically relevant traits in sheep breeding. This article presents material on the polymorphism of
the growth hormone gene (rs397514071) studied by PCR-RFLP on ten breeds of sheep (Stavropol, Manych Merino, Russian Meat Merino, North Caucasian meat and wool, Dagestan
mountain, Kalmyk fat-tailed, Kalmyk fat-tailed (crossbreds of ½ Kalmyk fat-tailed + ½ Charollais), Dzhalginsky Merino, Chernozemelsky Merino, Lacaune), which were bred in different
regions of the South of Russia. It was found that the allelic polymorphism of the growth hormone (GH) gene in sheep of the studied breeds was represented by two alleles GHA
and GHB
,
moreover the predominance of the GHA
allele was noted, the frequency of occurrence of
which varied from 0,53 to 1,0. The frequency of occurrence of the desirable homozygous
GHBB genotype in sheep samples was low and varied from complete absence in such breeds as
Dagestan mountain, Kalmyk fat-tailed, crossbreds of ½ Kalmyk fat-tailed + ½ Charollais,
Chernozemelsky Merino to the highest 30,0 and 34,0 % in North Caucasian meat and wool
and Stavropol breeds. The frequency of occurrence of the homozygous GHAA genotype ranged
from 24,0 to 100,0 %, whereas the heterozygous genotype ranged from 0,0 to 59,0 %. The
analysis of the genetic structure of the studied sheep populations of different breeds and different types of productivity according to the locus of the GH gene showed a significant deficiency of heterozygotes. The heterozygosity testing (HT) was negative (from -0,303 to -
0,677) in samples of sheep of the Manych Merino, Russian Meat Merino, Lacaune, North
Caucasian meat and wool and Stavropol breeds, but positive (+0,003; + 0,045; + 0,015) was
in sheep of the Chernozemelsky Merino, Dzhalginsky Merino and Dagestan mountain breed.