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Using 11 microsatellite markers (OarCP49, INRA063, HSC, OarAE129, MAF214, OarFCB11, INRA005, SPS113, INRA23, MAF65, and McM527), data on the level of variability and degree of differentiation of 24 populations (1140 specimens) of Tuvan coarse-wooled short fat-tailed sheep from different regions of the Republic of Tyva and 24 sheep breeds (721 specimens) of different origin from the main sheep-raising regions of the Russian Federation, were obtained. The analysis revealed the high level of genetic isolation and variability of Tuvan sheep. Moreover, in the general structure of Russian sheep breeds, pronounced genetic divergence into two large groups was revealed, with one of these groups uniting fine-fleeced and semi-fine-fleeced sheep, and the other group consisting of indigenous coarse-wooled breeds of North Caucasian and Asian origin. [ABSTRACT FROM AUTHOR]

For the first time, an analysis of the genetic diversity of the Osetin sheep breed was performed using genome-wide SNP profiles in a comparison with other Russian coarse wool breeds. We established that the Osetin breed has high indicators of genetic and allelic diversity. For the first time, the recent and historical effective sizes of the population of the Osetin breed were calculated. Close genetic relationships between the Osetin and Karachaev sheep breeds were shown, which is confirmed by the low value of differentiation (Fst = 0.009) and the formation of a joint cluster on the neighbor net graph. The similarity of the population structure of the Osetin and Karachaev breeds was revealed. [ABSTRACT FROM AUTHOR]

Summary: Copy number variants (CNVs) are genomic structural variations that contribute to many adaptive and economically important traits in livestock. In this study, we detected CNVs in 354 animals from 16 Russian indigenous sheep breeds and analysed their possible functional roles. Our analysis of the entire sample set resulted in 4527 CNVs forming 1450 CNV regions (CNVRs). When constructing CNVRs for individual breeds, a total of 2715 regions ranging from 88 in Groznensk to 337 in Osetin breeds were identified. To make interbreed CNVR frequency comparison possible, we also identified core CNVRs using CNVs with overlapping chromosomal locations found in different breeds. This resulted in 137 interbreed CNVRs with frequency >15% in at least one breed. Functional enrichment analysis of genes affected by CNVRs in individual breeds revealed 12 breeds with significant enrichments in olfactory perception, PRAME family proteins, and immune response. Function of genes affected by interbreed and breed‐specific CNVRs revealed candidates related to domestication, adaptation to high altitudes and cold climates, reproduction, parasite resistance, milk and meat qualities, wool traits, fat storage, and fat metabolism. Our work is the first attempt to uncover and characterise the CNV makeup of Russian indigenous sheep breeds. Further experimental and functional validation of CNVRs would help in developing new and improving existing sheep breeds. [ABSTRACT FROM AUTHOR]

Prolificacy is a very important trait in sheep. Romanov sheep, the well-known Russian sheep breed, are characterized by very high prolificacy; however, the genetic basis of this unique property of Romanov sheep is still unknown. It was reported that Ovine BMPR1B gene, located on the OAR6, is associated with prolificacy in several sheep breeds. The aim of our study was to identify candidate SNPs within BMPR1B gene, related to prolificacy. To achieve this goal, using NGS technology, we sequenced ovine BMPR1B gene in Romanov sheep (n = 6), which are characterized by high prolificacy (about 270 lambs per 100 ewes). The sequences of BMPR1B gene of Noire du Velay, Tan, Southdown and Australian Horned Merino sheep breeds as well as Asiatic mouflon (n = 1), which are characterized by significantly lower prolificacy (from 110 to 180 lambs per 100 ewes) were derived from publicly available sources and used for comparison. FST analysis performed in PLINK 1.9 program revealed 10 SNPs with values higher than 0.8. The majority of candidate SNPs under putative selection were localized in the region from 29,382,098 to 29,430,387 on OAR6 of Ovine reference genome (Oar_v3.1 (Ensembl release 98). Thus, we can suggest, that this region of the BMPR1B gene can be considered as the putative region, associated with high prolificacy of Romanov sheep. Additional studies will be needed to confirm the effect of identified candidate SNPs on prolificacy traits. The research results will be useful for artificial selection of sheep with higher prolific capacity, including the introduction of desired alleles in sheep populations using genome editing technologies. This work was supported by the Russian Ministry of Science and Higher Education No. 0445-2019-0024 and RFBR No. 20-516-56002. [ABSTRACT FROM AUTHOR]

Azerbaijani sheep breeds are of particular interest since this region is in close proximity to the Fertile Crescent - the proposed place of domestication. Molecular genetic studies of local breeds will help shed light on the history of sheep breeding. Our work was aimed to identify genetic characteristics of three sheep breeds from Azerbaijan: Bozakh (n = 19), Karabakh (n = 16) and Mazekh (n = 19). For genotyping, we used Illumina OvineHD BeadChip (AgResearch) containing around 600 thousand SNPs. PLINK 1.9 was used to perform quality control. Genetic diversity parameters and pairwise FST distances were calculated in R package diveRsity. After all quality control procedures, including LD pruning, 286663 SNPs were selected for subsequent analyses. PCA revealed that, while all the breeds formed their own clusters, only 1.62% of genetic variability was explained by the first component (PC1). Cluster analysis conducted in Admixture 1.3 showed that Bozakh was derived from Karabakh and Mazekh breeds. However, based on CV error, the number of clusters (K) judged to be one. Pairwise FST distances were quite low, with highest value of 0.017 between Karabakh and Mazekh and lowest (0.006) between Mazekh and Bozakh breeds. The global fixation index (FST) was 0.01, which indicated that 99% of genetic variability was due to within breeds differences. Expected heterozygosity was similar in Bozah and Mazeh (0.363±0.000 and 0.360±0.000, respectively) and a slight lower in Karabakh breed (0.353±0.000). We observed neither heterozygotes excess nor deficiency in all of the studied breeds. The inbreeding coefficient (Fis), ranged from 0.001 in Karabakh to 0.011 in Mazekh sheep. Our results demonstrate that the studied Azerbaijani sheep breeds are genetically close, but carry specific genomic components that allows consider them as valuable genetic resources. The study was funded by the RSF 21-66-00007 (genotyping) and the Russian Ministry of Science and Higher Education 0445-2019-0024 (expedition studies). [ABSTRACT FROM AUTHOR]

Karachaev sheep is a fat-tailed breed from North-Caucasus, Russia. It has good adaptability to local environments and excellent meat quality. The aim of our study was to investigate genetic characteristics of Karachaev sheep and its relationship with other fattailed breeds. Samples of Karachaev (n = 22), Lezgin (n = 21), Edilbai (n = 21), Karakul (n = 21), Alai (n = 20), and Gissar (n = 20) breeds were genotyped using Ovine HD BeadChip. For phylogenetic analyses, we additionally included 50K genotypes of Afshari, Awassi, Barki, Chios, Cyprus Fat-Tailed, and Red Maasai breeds. PLINK 1.9 was used for quality control and performing PCA. Genetic diversity parameters were calculated in R package diveRsity. Historical effective population size (Ne) was estimated using SNeP 1.1. Cluster analysis was conducted in Admixture 1.3. TreeMix tree was constructed in TreeMix 1.13. Genetic diversity indices (observed and expected heterozygosity, allelic richness) were highest in Karachaev and Lezgin breeds. Karachaev sheep was phylogenetically closer to Lezgin and Edilbai breeds. Trends in historical Ne were very similar for these breeds. We observed the increased decline in Ne around 20-25 generations ago (which corresponds to 1940s) that can be associated with deportation of Karachaev people to Kazakhstan and Kyrgyzstan in 1943, which resulted in lost almost all of its livestock. TreeMix analysis allowing one migration event revealed gene flow from Karakul to Karachaev/Lezgin nod. Admixture analysis showed the presence in Karachaev sheep of Edilbai and Karakul specific genomic components (~80 and ~20%, respectively). Our study allow suggest that Karachaev breed was extinct during World War II and then was restored in 1960s after Karachaev people returned to their land. It originated from the sheep they brought from Central Asia (Edilbai), and was improved by Karakul breed and local sheep. This work was supported by RSF No. 21-46-00001 (genotyping) and the Russian Ministry of Science and Higher Education No. 0445-2019-0024 (expedition studies). [ABSTRACT FROM AUTHOR]

The world-famous Romanov breed of sheep fits easily into different production systems including private households, smallholders, and large farms. Such a resilience and extraordinary reproduction traits combining with good meat qualities have made the Romanov breed as a choice to produce mutton in the Central Russia regions. However, little is known on genetic mechanisms underlying the complex of specific traits of this breed. In this regard, we performed a scan of signatures of selection by identification of runs of homozygosity (ROH) islands in the Romanov sheep population. Forty-eight samples of the Romanov sheep from the Yaroslavl and Kaluga regions of Russia were genotyped using Ovine Infinium® HD SNP BeadChip (Illumina, CA, USA). ROHs were estimated in the R package "detectRUNS" using window-free method for consecutive. The ROH shared in more than 50% of sheep were considered as ROH islands. The genes overlapped with the ROH islands were annotated using Ensembl genome browser 103. Enrichment for functional categories of the identified genes was performed using DAVID Functional Annotation Bioinformatics Microarray Analysis tool. More than 88 SNPs were found in ROH islands located on OAR1, OAR10, OAR11, OAR13, OAR14, OAR15, OAR16, OAR17 and OAR18. We detected a major group of genes related to reproduction traits. The identified candidates included UBE2Q1 (embryo implantation, fertilization, prolactin secretion), RNF17 (spermiogenesis), HSD11B2 (pregnancy, follicle function), FANCA (gonad development), and CUBN (embryonic development). In addition, several identified genes were involved in fatty acid metabolism (ACOX1, HAO2, and EIF6), lipid transport (OSBPL11), and biosynthesis of lipid-binding serum glycoproteins (BPIFB4) as well as in osteoblast differentiation (ADAR). The studies will be continued on a larger sample with further validation of the most promising candidate genes. Genotyping of twenty-four samples was performed within RFBR project No. 20-516-56002. Other twenty-four SNP-genotypes were generated within the theme No. 0445-2019-0024. [ABSTRACT FROM AUTHOR]

Maintaining high levels of genetic diversity is a key factor of successful breeding of resilient, resistant to diseases and productive sheep. Prevention of inbreeding is of special importance in the mountainous hard-to-get habitats where gene flow is limited or absent. An assessment of inbreeding coefficients based only on pedigree information is not always correct. In addition, pedigree information is often missing for flocks of native sheep. In this regard, we performed a genomic assessment of inbreeding in 15 local sheep breeds inhabiting severe environments of Russia and neighboring Asian countries based on estimations of standardized multilocus heterozygosity (sMLH) and runs of homozygosity [F(ROH)]. For this study, we used SNP genotypes of twelve Russian local breeds (n = 316) and three Kyrgyz local breeds (n = 68), which were generated using Ovine Infinium® HD SNP BeadChip (Illumina, CA, USA). The sMLH values were calculated using R package inbreedR and visualized in R package ggplot2. The F(ROH) values were calculated using the R package detectRUNS by applying the consecutive runs method. Mean sMLH values were varied from 0.962 ± 0.006 in the Andean breed to 1.031 ± 0.002 in the Buryat breed and averaged to 1.001± 0.004. The least mean F(ROH) value was detected in the Mongolian breed (0.0043 ± 0.0009) while the greatest ones were observed in the Alai and Andean breeds (0.0364 ± 0.0049 and 0.0357 ± 0.0061, respectively). The strong negative correlations between sMLH and F(ROH) were detected for all of studied breeds (r2 = -0.8496, CI = -0.8752... -0.8192). The obtained data is relevant for control of inbreeding level in the populations and for future sustainable management of native fat-tailed sheep breeds. The study was funded by RSF No. 19-16-00070. [ABSTRACT FROM AUTHOR]

The Romanov breed stands out from the global variety of sheep breeds. Romanovs originated from local sheep at the end of 17th century in the Volga Valley. Since the 1970s, the breed has become popular in France, Canada, and the United States. Some unique traits are of permanent interest to this Russian breed. Primarily, Romanovs have outstanding reproduction qualities: early sexual maturity, out-of-season breeding ability, and extraordinary prolificacy. Using Romanov ewes in crossbreeding programs is a profitable, practical method to increase the number of highly viable hybrids. In addition, the Romanov breed has unique wool properties, which are very suitable for manufacturing felt products, rugs, and mats. However, detailed genetic information on the breed is lacking. Therefore, we performed the whole-genome SNP analysis of the original Romanov sheep to study its genetic diversity and genetic relationships with other Russian breeds. We genotyped 42 samples of Romanovs using the OvineSNP50K BeadChip and pooled the data with the set from 24 Russian breeds. Quality filtering was performed in PLINK version 1.07. Calculations were done in PLINK version 1.07, GENETIX version 4.05, and HP-Rare 1.1. We found a lower level of genetic diversity in Romanovs (Ho = 0.350 and Ar = 1.862) in comparison with other coarse wool breeds (Ho = 0.377 and Ar = 1.899). At the same time, Romanovs, compared with the 24 breeds, were characterized by the most insignificant deviation from Hardy-Weinberg equilibrium (Fis = -0.005). In other breeds, Fis values varied from -0.028 to -0.082. Pairwise Fst values ranged from 0.084 to 0.124 between Romanovs and Kuibyshev and Kuchugur, respectively. The MDS analysis revealed the genetic uniqueness of Romanov sheep. Principal component (PC) 1 divided all breeds into 2 groups according the wool type (fine wool + semifine wool and coarse wool) with 4.7% of total genetic variance. By PC1 the Romanov formed an incorporated bunch and logically clustered with coarse-wool breeds. However, the Romanov was clearly separated from the others by PC2, which explained 3.8% of additional genetic variability. Most likely, a high level of consolidation and genetic differentiation of the Romanov breed from other Russian sheep are explained by its "pure gene" origin and was not improved by any breed. Our study is the first attempt to reveal the outstanding genetic nature of original Romanov sheep on whole-genome level. We will extend our study by genotyping more samples with medium-density DNA chip and using NGS technology. The research was performed under financial support of Russian Scientific Foundation (number 14-36-00039). [ABSTRACT FROM AUTHOR]

Background: Domestication and centuries of selective breeding have changed genomes of sheep breeds to respond to environmental challenges and human needs. The genomes of local breeds, therefore, are valuable sources of genomic variants to be used to understand mechanisms of response to adaptation and artificial selection. As a step toward this we performed a high-density genotyping and comprehensive scans for signatures of selection in the genomes from 15 local sheep breeds reared across Russia. Results: Results demonstrated that the genomes of Russian sheep breeds contain multiple regions under putative selection. More than 50% of these regions matched with intervals identified in previous scans for selective sweeps in sheep genomes. These regions contain well-known candidate genes related to morphology, adaptation, and domestication (e.g., KITLG, KIT, MITF, and MC1R), wool quality and quantity (e.g., DSG@, DSC@, and KRT@), growth and feed intake (e.g., HOXA@, HOXC@, LCORL, NCAPG, LAP3, and CCSER1), reproduction (e.g., CMTM6, HTRA1, GNAQ, UBQLN1, and IFT88), and milk-related traits (e.g., ABCG2, SPP1, ACSS1, and ACSS2). In addition, multiple genes that are putatively related to environmental adaptations were top-ranked in selected intervals (e.g., EGFR, HSPH1, NMUR1, EDNRB, PRL, TSHR, and ADAMTS5). Moreover, we observed that multiple key genes involved in human hereditary sensory and autonomic neuropathies, and genetic disorders accompanied with an inability to feel pain and environmental temperatures, were top-ranked in multiple or individual sheep breeds from Russia pointing to a possible mechanism of adaptation to harsh climatic conditions. Conclusions: Our work represents the first comprehensive scan for signatures of selection in genomes of local sheep breeds from the Russian Federation of both European and Asian origins. We confirmed that the genomes of Russian sheep contain previously identified signatures of selection, demonstrating the robustness of our integrative approach. Multiple novel signatures of selection were found near genes which could be related to adaptation to the harsh environments of Russia. Our study forms a basis for future work on using Russian sheep genomes to spot specific genetic variants or haplotypes to be used in efforts on developing next-generation highly productive breeds, better suited to diverse Eurasian environments. [ABSTRACT FROM AUTHOR]

Background: Russia has a diverse variety of native and locally developed sheep breeds with coarse, fine, and semi-fine wool, which inhabit different climate zones and landscapes that range from hot deserts to harsh northern areas. To date, no genome-wide information has been used to investigate the history and genetic characteristics of the extant local Russian sheep populations. To infer the population structure and genome-wide diversity of Russian sheep, 25 local breeds were genotyped with the OvineSNP50 BeadChip. Furthermore, to evaluate admixture contributions from foreign breeds in Russian sheep, a set of 58 worldwide breeds from publicly available genotypes was added to our data. Results: We recorded similar observed heterozygosity (0.354–0.395) and allelic richness (1.890–1.955) levels across the analyzed breeds and they are comparable with those observed in the worldwide breeds. Recent effective population sizes estimated from linkage disequilibrium five generations ago ranged from 65 to 543. Multi-dimensional scaling, admixture, and neighbor-net analyses consistently identified a two-step subdivision of the Russian local sheep breeds. A first split clustered the Russian sheep populations according to their wool type (fine wool, semi-fine wool and coarse wool). The Dagestan Mountain and Baikal fine-fleeced breeds differ from the other Merino-derived local breeds. The semi-fine wool cluster combined a breed of Romanian origin, Tsigai, with its derivative Altai Mountain, the two Romney-introgressed breeds Kuibyshev and North Caucasian, and the Lincoln-introgressed Russian longhaired breed. The coarse-wool group comprised the Nordic short-tailed Romanov, the long-fat-tailed outlier Kuchugur and two clusters of fat-tailed sheep: the Caucasian Mountain breeds and the Buubei, Karakul, Edilbai, Kalmyk and Tuva breeds. The Russian fat-tailed breeds shared co-ancestry with sheep from China and Southwestern Asia (Iran). Conclusions: In this study, we derived the genetic characteristics of the major Russian local sheep breeds, which are moderately diverse and have a strong population structure. Pooling our data with a worldwide genotyping set gave deeper insight into the history and origin of the Russian sheep populations. [ABSTRACT FROM AUTHOR]