Study of phenotypic and genotypic features of reindeer populations of the Nenets breed

Reindeer herding is the leading branch of animal husbandry in the Nenets Autonomous Okrug (NAO). Currently, reindeer herding is being conducted mainly by traditional methods, which are based on the assessment of the phenotype. For further development of reindeer herding and the increase of its productivity, it is necessary to improve the level of breeding work by using molecular genetic information. The aim of our study was to investigate the phenotypic and genetic features of the reindeer Nenets breed in the conditions of the NAO. To examine morphological features, the measurements of the exterior characteristics (height at withers, chest depth, chest width, chest girth, wrist girth, body length, loin width, head length, body weight) were made at three farms of the NAO: ERV (ERV, n = 28), Indiga (IND, n = 34) and Ilebts (ILB, n = 25). Based on the data obtained, the body built indices were calculated: massiveness, blockiness, bone, chest index, lengthiness and head. For genetic characteristics, the analysis of nine microsatellite (NVHRT76, RT9, NVHRT24, RT30, RT1, RT6, RT27, NV21, RT7) loci was carried out. Statistical processing of data was performed using the R software and R packages adegenet and diveRsity. For most of the exterior features, a significant advantage of IND and ILB over ERV was observed, respectively: height at withers - 99.2±0.42, 99.7±0.53 and 97.0±0.46 cm (p 0.01); chest depth - 43.4±0.31, 42.6±0.32 and 43.7±0.46 cm; chest width - 27.7±0.35, 27.5±0.45 and 26.6±0.27 cm; chest girth - 125.6±0.69, 126.6±0.80 and 119.0±0.77 cm (p 0.01); body length - 108.3±0.54, 107.7±0.81 and 102.2±0.32 cm (p 0.01); wrist girth - 11.8±0.09, 11.9±0.11 and 11.21±0.05 cm; head length - 33.3±0.38, 33.9±0.51 and 32.1±0.18 cm; body weight is 104.6±1.17, 106.4±1.24 and 83.5±1.08 cm (p 0.01). IND and ILB also exceeded ERV (p 0.01) in massiveness, chest and lengthiness indices. As compared to the indicators of the 1970s, there was an increase in massiveness and chest index in IND and ILB, and bone and lengthiness in all the three groups studied. According to the results of principal component analysis (PCA), the similarity between IND and ILB was observed for both the morphological and genetic characteristics, which was manifested in the formation of overlapping arrays on the PCA-plot, while the ERV formed a relatively isolated cluster. Pairwise genetic distances confirmed the greater similarity between IND and ILB (Fst - 0.018 and DJost - 0.017). All the three populations were characterized by a deficit of heterozygotes (Fis 0, CI 95 %). Allelic richness (Ar) varied from 6.17±0.499 (IND) to 6.78±0.494 (ILB). Thus, it was shown that the reindeer populations that are bred in the NAO have morphological and genetic differences. In addition, the populations with different morphological characteristics were not close genetically. Morphological features in the studied populations were within the breed standards, or exceeded them