Study of mtDNA COI Gene Polymorphism and Relationship With Some Productive Traits in Awassi Sheep

Abstract

Abstract This study was carried out in two locations (the field part), first in the Ruminants Researches Station (20 km west of Baghdad), and the second in the Aldawar research station located in Anbar governorate (Up to 35 km west of Ramadi city), which included 87 animals from Awassi sheep. As for the laboratory part, it took place in two locations, the first in the Animal Breeding and Improvement Laboratory of the Ruminant Research Department, and the second in the Scientific Progress Laboratory/Baghdad. This study aimed to investigate the relationship between polymorphism of mtDNA-COI gene and growth traits, milk yield, and lactation period in Awassi sheep. DNA was extracted from the blood and the polymerase Chain Reaction (PCR) technique was used to amplify the COI gene. DNA sequencing analysis. The results showed that there are 6 SNPs in a COI gene, there polymorphism for this gene also appeared (TT, CC). The 1st site (5566), CC polymorphism achieved the highest percentages (39.09) compared with TT polymorphism, with an allelic frequency of 0.57. While it appeared in the 2nd, 3rd, 4th, and 6th sites the polymorphism TT and CC with percentages (79.31 and 20.69)%, (58.42 and 41.38)%, (20.69 and 79.31), (79.31 and 20.69)%, and with the allele frequency (0.79 and 0.21), (0.59 and 0.41), (0.21 and 0.79), (0.79 and 0.21) respectively. there were significant differences (P<0.05) of COI polymorphism in birth weight, weaning weight and gain from birth to weaning as the TT recorded the highest average for both traits (3.82, 25.39 and 21.57 kg respectively). The mean of daily milk yield for TT polymorphism was 330.21 gm/day, which significant (P<0.05) the CC polymorphism, no significant between COI polymorphism and lactation period. It was possible to conclude from this study the possibility of COI gene polymorphism in the development of genetic improvement strategies and breeding programs that achieved the best productive performance sheep.