Analysis of genome-wide DNA arrays reveals the genomic population structure and diversity in autochthonous Greek goat breeds.
ABSTRACT: Goats play an important role in the livestock sector in Greece. The national herd consists mainly of two indigenous breeds, the Eghoria and Skopelos. Here, we report the population structure and genomic profiles of these two native goat breeds using Illumina's Goat SNP50 BeadChip. Moreover, we present a panel of candidate markers acquired using different genetic models for breed discrimination. Quality control on the initial dataset resulted in 48,841 SNPs kept for downstream analysis. Principal component and admixture analyses were applied to assess population structure. The rate of inbreeding within breed was evaluated based on the distribution of runs of homozygosity in the genome and respective coefficients, the genomic relationship matrix, the patterns of linkage disequilibrium, and the historic effective population size. Results showed that both breeds exhibit high levels of genetic diversity. Level of inbreeding between the two breeds estimated by the Wright's fixation index FST was low (Fst = 0.04362), indicating the existence of a weak genetic differentiation between them. In addition, grouping of farms according to their geographical locations was observed. This study presents for the first time a genome-based analysis on the genetic structure of the two indigenous Greek goat breeds and identifies markers that can be potentially exploited in future selective breeding programs for traceability purposes, targeted genetic improvement schemes and conservation strategies.
Project description:Selection for performance in diverse production settings has resulted in variation across sheep breeds worldwide. Although sheep are an important species to the United States, the current genetic relationship among many terminal sire breeds is not well characterized. Suffolk, Hampshire, Shropshire and Oxford (terminal) and Rambouillet (dual purpose) sheep (n = 248) sampled from different flocks were genotyped using the Applied Biosystems Axiom Ovine Genotyping Array (50K), and additional Shropshire sheep (n = 26) using the Illumina Ovine SNP50 BeadChip. Relationships were investigated by calculating observed heterozygosity, inbreeding coefficients, eigenvalues, pairwise Wright's FST estimates and an identity by state matrix. The mean observed heterozygosity for each breed ranged from 0.30 to 0.35 and was consistent with data reported in other US and Australian sheep. Suffolk from two different regions of the United States (Midwest and West) clustered separately in eigenvalue plots and the rectangular cladogram. Further, divergence was detected between Suffolk from different regions with Wright's FST estimate. Shropshire animals showed the greatest divergence from other terminal breeds in this study. Admixture between breeds was examined using admixture, and based on cross-validation estimates, the best fit number of populations (clusters) was K = 6. The greatest admixture was observed within Hampshire, Suffolk, and Shropshire breeds. When plotting eigenvalues, US terminal breeds clustered separately in comparison with sheep from other locations of the world. Understanding the genetic relationships between terminal sire breeds in sheep will inform us about the potential applicability of markers derived in one breed to other breeds based on relatedness.
Project description:Polymorphisms at PRNP gene locus have been associated with resistance against classical scrapie in goats. Genetic selection on this gene within appropriate breeding programs may contribute to the control of the disease. The present study characterized the genetic profile of codons 146, 211 and 222 in three dairy goat breeds in Greece. A total of 766 dairy goats from seven farms were used. Animals belonged to two indigenous Greek, Eghoria (n = 264) and Skopelos (n = 287) and a foreign breed, Damascus (n = 215). Genomic DNA was extracted from blood samples from individual animals. Polymorphisms were detected in these codons using Real-Time PCR analysis and four different Custom TaqMan® SNP Genotyping Assays. Genotypic, allelic and haplotypic frequencies were calculated based on individual animal genotypes. Chi-square tests were used to examine Hardy-Weinberg equilibrium state and compare genotypic distribution across breeds. Genetic distances among the three breeds, and between these and 30 breeds reared in other countries were estimated based on haplotypic frequencies using fixation index FST with Arlequin v3.1 software; a Neighbor-Joining tree was created using PHYLIP package v3.695. Level of statistical significance was set at P = 0.01. All scrapie resistance-associated alleles (146S, 146D, 211Q and 222K) were detected in the studied population. Significant frequency differences were observed between the indigenous Greek and Damascus breeds. Alleles 222K and 146S had the highest frequency in the two indigenous and the Damascus breed, respectively (ca. 6.0%). The studied breeds shared similar haplotypic frequencies with most South Italian and Turkish breeds but differed significantly from North-Western European, Far East and some USA goat breeds. Results suggest there is adequate variation in the PRNP gene locus to support breeding programs for enhanced scrapie resistance in goats reared in Greece. Genetic comparisons among goat breeds indicate that separate breeding programs should apply to the two indigenous and the imported Damascus breeds.
Project description:Both natural and artificial selection are among the main driving forces shaping genetic variation across the genome of livestock species. Selection typically leaves signatures in the genome, which are often characterized by high genetic differentiation across breeds and/or a strong reduction in genetic diversity in regions associated with traits under intense selection pressure. In this study, we evaluated selection signatures and genomic inbreeding coefficients, FROH, based on runs of homozygosity (ROH), in six Ugandan goat breeds: Boer (n = 13), and the indigenous breeds Karamojong (n = 15), Kigezi (n = 29), Mubende (n = 29), Small East African (n = 29), and Sebei (n = 29). After genotyping quality control, 45,294 autosomal single nucleotide polymorphisms (SNPs) remained for further analyses. A total of 394 and 6 breed-specific putative selection signatures were identified across all breeds, based on marker-specific fixation index (FST-values) and haplotype differentiation (hapFLK), respectively. These regions were enriched with genes involved in signaling pathways associated directly or indirectly with environmental adaptation, such as immune response (e.g., IL10RB and IL23A), growth and fatty acid composition (e.g., FGF9 and IGF1), and thermo-tolerance (e.g., MTOR and MAPK3). The study revealed little overlap between breeds in genomic regions under selection and generally did not display the typical classic selection signatures as expected due to the complex nature of the traits. In the Boer breed, candidate genes associated with production traits, such as body size and growth (e.g., GJB2 and GJA3) were also identified. Furthermore, analysis of ROH in indigenous goat breeds showed very low levels of genomic inbreeding (with the mean FROH per breed ranging from 0.8% to 2.4%), as compared to higher inbreeding in Boer (mean FROH = 13.8%). Short ROH were more frequent than long ROH, except in Karamojong, providing insight in the developmental history of these goat breeds. This study provides insights into the effects of long-term selection in Boer and indigenous Ugandan goat breeds, which are relevant for implementation of breeding programs and conservation of genetic resources, as well as their sustainable use and management.
Project description:Sudan is endowed with a variety of indigenous goat breeds which are used for meat and milk production and which are well adapted to the local environment. The aim of the present study was to determine the genetic diversity and relationship within and between the four main Sudanese breeds of Nubian, Desert, Taggar and Nilotic goats. Using the 50 K SNP chip, 24 animals of each breed were genotyped.More than 96% of high quality SNPs were polymorphic with an average minor allele frequency of 0.3. In all breeds, no significant difference between observed (0.4) and expected (0.4) heterozygosity was found and the inbreeding coefficients (FIS) did not differ from zero. Fst coefficients for the genetic distance between breeds also did not significantly deviate from zero. In addition, the analysis of molecular variance revealed that 93% of the total variance in the examined population can be explained by differences among individuals, while only 7% result from differences between the breeds. These findings provide evidence for high genetic diversity and little inbreeding within breeds on one hand, and low diversity between breeds on the other hand. Further examinations using Nei's genetic distance and STRUCTURE analysis clustered Taggar goats distinct from the other breeds. In a principal component (PC) analysis, PC1 could separate Taggar, Nilotic and a mix of Nubian and Desert goats into three groups. The SNPs that contributed strongly to PC1 showed high Fst values in Taggar goat versus the other goat breeds. PCA allowed us to identify target genomic regions which contain genes known to influence growth, development, bone formation and the immune system.The information on the genetic variability and diversity in this study confirmed that Taggar goat is genetically different from the other goat breeds in Sudan. The SNPs identified by the first principal components show high Fst values in Taggar goat and allowed to identify candidate genes which can be used in the development of breed selection programs to improve local breeds and find genetic factors contributing to the adaptation to harsh environments.
Project description:Goat breeding has become an important sector in Eastern Europe, with Romania and Hungary being among the major producer countries. Given the limited number of research done up-to-date concerning genetic studies of indigenous goat breeds reared in Romania and Hungary, the current preliminary study aimed to analyze the variability of genes related to mastitis and gastrointestinal parasitism by using Kompetitive Allele Specific PCR (KASP™). We studied 52 single nucleotide polymorphisms (SNPs) belonging to 19 genes in indigenous breeds from both countries, namely Banat's White (n = 36), Carpatina (n = 35) from Romania and Hungarian Milking (n = 79) and identified 16 polymorphic SNPs among 10 genes (PTX3, IL6, CLEC4E, IL8, IL1RN, IL15RA, TNFSF13, SOCS3, TNF and TLR3) in 150 animals. Furthermore, the diversity of the studied breeds was investigated. The PIC values ranged from 0.042 to 0.691. The mean values of observed and expected heterozygosity were 0.235 and 0.246 respectively. The highest observed heterozygosity was obtained for IL15RA g.10343904C>T in Banat's White (0.464), IL15RA g.10354813C>T in Carpatina (0.577) and SOCS3 g.52626440T>G in Hungarian Milking (0.588). Pairwise FST values between the Romanian breeds and Romanian and Hungarian breeds were small (0.009 and 0.015), indicating the close relationship among the studied goat populations. From all the polymorphic SNPs identified, the Hungarian Milking breed showed the highest proportion of polymorphisms (100%), whereas the Carpatina breed had the lowest percentage (87.5%). The highest value of MAF was obtained for SOCS3 g.52626440T>G (0.46), IL15RA g.10343904C>T (0.47), IL15RA g.10344025C>T (0.45), and IL15RA g.10354813C>T (0.42). The 16 polymorphic SNPs identified in a panel of 150 unrelated individuals belonging to three Romanian and Hungarian indigenous goat breeds could be used in future genomic based breeding schemes as markers for genetic resistance to mastitis and gastrointestinal parasitism in goat breeds found in Eastern and Central Europe.
Project description:North Africa represents a rich and early reservoir of goat genetic diversity, from which the main African breeds have been derived. In this study, the genetic diversity of four indigenous Algerian goat breeds (i.e., Arabia, Makatia, M'Zabite and Kabyle, with n = 12 for each breed) has been investigated for the first time by genome-wide SNP genotyping; moreover in a broader context, genetic structuration of Algerian and Moroccan goats was explored (via FST, MDS, STRUCTURE, FineSTRUCTURE, BAPS, sPCA and DAPC analyses). At national level, the study revealed high level of genetic diversity and a significant phenomenon of admixture affecting all the Algerian breeds. At broader scale, clear global genetic homogeneity appeared considering both Algerian and Moroccan stocks. Indeed, genetic structuration was almost nonexistent among Arabia (from Algeria), Draa, Black and Nord (from Morocco), while the ancestral Kabyle and M'Zabite breeds, reared by Berber peoples, showed genetic distinctness. The study highlighted the threat to the Maghrebin stock, probably induced by unsupervised cross-breeding practices which have intensified in recent centuries. Moreover, it underlined the necessity to deepen our understanding of the genetic resources represented by the resilient North-African goat stock.
Project description:Due to its rarity and unique biological traits, as well as its growing financial value, milk of dairy Greek small ruminants is continuously attracting interest from both the scientific community and industry. For the construction of the present dataset, cutting-edge proteomics methodologies were employed, in order to investigate and characterize, for the first time, the milk whey proteome from the two indigenous Greek goat breeds, Capra prisca and Skopelos. In total 822 protein groups were identified in milk whey of the two breeds, The present data are further discussed in the research article "Milk of Greek sheep and goat breeds; characterization by means of proteomics" .
Project description:Objective:An experiment was conducted to evaluate genetic diversity of 26 Chinese indigenous goats by 30 microsatellite markers, and then to define conservation priorities to set up the protection programs according to the weight given to within- and between-breed genetic diversity. Methods:Twenty-six representative populations of Chinese indigenous goats, 1351 total, were sampled from different geographic regions of China. Within-breed genetic diversity and marker polymorphism were estimated calculating the mean number of alleles (MNA), observed heterozygosities (HO), expected heterozygosities (He), fixation index (FIS), effective number of alleles (NE) and allelic richness (Rt). Conservation priorities were analyzed by statistical methods. Results:A relatively high level of genetic diversity was found in twenty-four populations, the exceptions were in the Daiyun and Fuqing goat populations. Within-breed kinship coefficients matrix identified seven highly inbred breeds which should be concerned. Of these, six breeds will get a negative contribution to heterozygosity when the method was based on proportional contribution to heterozygosity. Based on Weitzman or Piyasatian and Kinghorn methods, the breeds distant from others i.e. Inner Mongolia Cashmere goat, Chengdu Brown goat and Leizhou goat will obtain a high ranking. Evidence from Caballero and Toro and Fabuel et al. method prioritized Jining Gray goat, Liaoning Cashmere goat and Inner Mongolia Cashmere goat, that in agreement with results from Kinship-based methods. Conclusion:Conservation priorities had planned according to multiple methods. Our results suggest Inner Mongolia Cashmere goat (most methods), Jining Gray goat and Liaoning Cashmere goat (high contribution to heterozygosity and total diversity) should be prioritized based on most methods. Furthermore, Daiyun goat and Shannan White goat also should be prioritized based on consideration of effective population size. However, if one breed could survive in changing conditions all the time, the straightforward approach is to increase its utilization and attraction for production via mining breed germplasm characteristic.
Project description:The Chongming white goat (CM) is an indigenous goat breed exhibits unique traits that are adapted to the local environment and artificial selection. By performing whole-genome re-sequencing, we generated 14-20× coverage sequences from 10 domestic goat breeds to explore the genomic characteristics and selection signatures of the CM breed. We identified a total of 23,508,551 single-nucleotide polymorphisms (SNPs) and 2,830,800 insertion-deletion mutations (indels) after read mapping and variant calling. We further specifically identified 1.2% SNPs (271,713) and 0.9% indels (24,843) unique to the CM breed in comparison with the other nine goat breeds. Missense (SIFT < 0.05), frameshift, splice-site, start-loss, stop-loss, and stop-gain variants were identified in 183 protein-coding genes of the CM breed. Of the 183, 36 genes, including AP4E1, FSHR, COL11A2, and DYSF, are involved in phenotype ontology terms related to the nervous system, short stature, and skeletal muscle morphology. Moreover, based on genome-wide F ST and pooled heterozygosity (Hp) calculation, we further identified selection signature genes between the CM and the other nine goat breeds. These genes are significantly associated with the nervous system (C2CD3, DNAJB13, UCP2, ZMYND11, CEP126, SCAPER, and TSHR), growth (UCP2, UCP3, TSHR, FGFR1, ERLIN2, and ZNF703), and coat color (KITLG, ASIP, AHCY, RALY, and MC1R). Our results suggest that the CM breed may be differentiated from other goat breeds in terms of nervous system owing to natural or artificial selection. The whole-genome analysis provides an improved understanding of genetic diversity and trait exploration for this indigenous goat breed.
Project description:Aim:This study is aimed at characterizing the genetic and phylogenetic structure of Lakor goats as indigenous livestock from the Southwest Maluku Regency based on mitochondrial COI gene sequences. Materials and Methods:The genomes of 103 follicle samples from Lakor goats, collected from Lakor Island, were analyzed. The polymerase chain reaction was used to amplify 1548 bp of the mitochondrial COI gene using two primer pairs (COIA and COIB). Following sequencing, genetic variation and phylogenetic relationship were established using MEGA version X software. Results:The results of multiple COI gene alignment of the total sequences identified four polymorphic nucleotides that function as genetic markers between individual animals within the Lakor goat population. These correspond to positions 228 (A-G), 519 (G-A), 900 (C-T), and 1266 (T-C). Phylogenetic signals based on the COI gene showed that Lakor goat breed is a monophyletic group or single clade with a bootstrap value of 100% by the neighbor-joining (NJ) and maximum likelihood (ML) evolutionary models. This data indicated that evolutionarily, the Lakor goat breed has a very close kinship with three goat breeds from China: The Meigu goat (KM 244714.1), Chinese Tibet (Capra hircus) (KJ 940969.1), and C. hircus (KP 677510.1). Phylogenetic information based on the cladistics system classified the Lakor goat as a single clade (monophyletic group). The low-genetic diversity within populations indicates that there has been an inbreeding depression occurring at a very high frequency. Conclusion:We conclude that the Lakor goat may be divided into a single clade or monophyletic group based on the COI gene sequence. Four nucleotides were identified that can be used as genetic markers among individual animals within the Lakor goat population, as well as C. hircus and others as derived from GenBank data. The Lakor goat population has a high level of inbreeding depression as a result of geographical isolation, which supports the formation of a monophyletic group with different genetic characteristics, and does not allow the introduction of males from other breeds. Phylogenetic signals indicated that Capra aegagrus (bezoar) is the ancestor of the native goats in Indonesia, including the Lakor goats.