In dairy farming, reproductive efficiency is vital to both profitability and sustainability. However, years of selective breeding for increased milk yield have adversely affected reproductive potential. This study aimed to pinpoint genomic regions and identify potential candidate genes associated with reproductive traits in Chinese Holstein cattle. In this study, a single-step genome-wide association study (ssGWAS) was conducted using 33,202 phenotypic records from 16,379 animals, 55,244 pedigree records, and genomic data from 1,698 cows. These data were integrated into the ssGWAS analysis, resulting in a total pedigree structure of 21,635 animals. A total of 12 significant markers were identified for calving interval (IC), days open (DO), number of services per conception (NS), and conception rate (CR). Among these significant SNPs, 3 SNPs were for IC, 2 SNPs were for DO, 3 SNPs were for NS, and 4 SNPs were for CR. Several promising candidate genes located near these SNPs have been identified, including SFXN4, B3GAT2, GRK5, PRDX3, and MTHFD1L, highlighting their potential involvement in fertility-related biological processes. Furthermore, functional enrichment analysis identified significant enrichment of pathways associated with cell adhesion and embryonic development, suggesting a potential mechanistic role for DSG family members (DSG1, DSG2, DSG3, and DSG4) in fertility regulation. Collectively, our findings enhance understanding of the complex genetic basis of reproductive traits in dairy cattle and may offer a valuable set of genomic targets for precision breeding of Chinese Holsteins. Integrating these markers into genomic selection programs may contribute to genetic improvements in reproductive efficiency and support the long-term sustainability of dairy production.
Feed efficiency traits are increasingly important in pig production for improving profitability and environmental sustainability. Understanding their genetic basis is crucial for uncovering underlying biological mechanisms and informing selection strategies. In this study, we analyzed residual feed intake (RFI), feed conversion ratio (FCR), and average daily feed intake (ADFI) in 201 animals. Three separate Bayesian GWASs were conducted using 29,844 SNPs in a case–control design, with the lowest and highest 15% of the phenotypic distribution selected as controls and cases (N = 30 per group), respectively, for each trait. The results confirmed the polygenic nature of the traits, identifying 4 SNPs for RFI on Sus scrofa chromosomes (SSC) 3, 13, and 15 with high posterior probability for the direction of their effects; 4 SNPs for FCR on SSC 8, 14, and 17; and 8 SNPs for ADFI on SSC 1, 2, 6, 8, and 11. A candidate gene search identified 41 potential genes involved in diverse biological processes, including feed efficiency, intestinal development, tissue remodeling and integrity, nutrient transport and absorption, metabolic homeostasis, cellular signaling, energy sensing, and neurological regulation. These genes formed a highly interconnected network, highlighting the complexity of feed efficiency and the interplay among multiple physiological, metabolic, and regulatory pathways.
S. Faggion, V. Bonfatti, A. Bergamasco et al.· Animals· 0 citations
Teat number is a key reproductive trait for the commercial pig industry, as an optimum number enhances weaned piglet survival rate. This study aimed to identify single nucleotide polymorphisms (SNPs) and genomic regions that are associated with teat number in the Large White sow. A total of 1000 French Large White sows were used in an analysis of total, left/right, and maximum unilateral teat number. Environmental factor, Spearman correlation, genome-wide association study (GWAS), linkage disequilibrium, and selective sweep analyses were conducted, with validation performed in a population of 1145 Landrace pigs. Genetic statistics showed that this population's teat number had moderate-low genomic heritability (h2 = 0.17-0.21) and weak negative correlation with weaned piglet litter weight. Parity and season affected teat development. GWAS identified 17 candidate SNPs on SSC 4, 7, and 17. Combined with selective sweep analysis, two key regions on SSC 7 were found, with four teat number-related SNPs, annotated to VRTN, DIO2, NRXN3. These candidate genes are associated with thoracic vertebrae development, hormone regulation during the early stage of teat formation, and nervous system development. These five SNPs showed similar results in the Landrace pig validation population; non-mutant homozygotes had 0.25-1.15 more teats than mutant ones in both populations. This study contributes to the identification of key variant loci associated with teat number-related traits in sows, thereby providing reliable molecular markers and a theoretical basis for marker-assisted selection of sow reproductive performance.
Simple Summary Growth and body conformation traits are important determinants of meat production and economic performance in sheep. Understanding their genetic basis can enhance breeding efficiency and support sustainable genetic improvement. In this study, we conducted a genome-wide association study (GWAS) to identify genomic regions associated with seven growth and body conformation traits in 401 sheep from four populations: Qira Black, Kyrgyz, Dorset × Hu crossbred, and Suffolk × Karakul crossbred sheep. After genotype quality control, 47,674 SNP markers were analyzed using a mixed linear model accounting for population structure and genetic relatedness. A total of 44 independent genomic regions were detected at a nominal significance threshold, containing 112 candidate genes potentially involved in skeletal development, cartilage formation, muscle growth, and metabolic regulation.
Erkinbay Azbergenov, Tao Jiang, Rui-zhi Yang et al.· Animals· 0 citations
Objective
Litter size is a key trait for evaluating reproductive performance of goats, which can directly influence the breeding efficiency and profitability of production cycles. However, a comprehensive understanding of its genetic architecture, including the causative mutations and their functional impacts, remains scarce, thus hindering its application in precision breed-ing.
Methods
A total of 92 female Leizhou goats were genotyped through whole-genome se-quencing (WGS), and their litter size were measured for three consecutive births. Subsequently, based on the genotype and phenotype data, population genetic structure analysis, selection signature analysis, and genome-wide association study (GWAS) were performed.
Results
We identified a total of 20,802,514 SNPs in the 92 Leizhou goats. Analysis of genetic structure revealed that the high-litter-size group exhibited greater genetic diversity than the low-litter-size group, although no significant genetic differentiation was detected between them. We identified 340 putative selective regions and 346 candidate genes across the genome. A total of 37 candidate genes were identified as being closely associated with reproductive traits, including BMP6, MAPK8, RPTOR, etc. In GWAS results, we identified 63 quantitative trait loci (QTLs) for litter size at suggestive significance (P＜1×10-5). After, 207 candidate genes were annotated, and 4 of them were highlighted that have been previously reported to be associated with reproductive processes (e.g., TMEM100, PDGFD, NLRP9, and ARHGAP22). By integrating the results from both approaches, we identified MAPK8 as a potential candidate gene associated with litter size. Furthermore, our findings from motif recognition, transcrip-tion factor prediction, and previous studies lead us to propose that the BMP6-GATA4-MAPK8 signaling pathway may play a key role in regulating litter size in goats.
Conclusion
Our findings identify several candidate genes and putative associated variants for litter size, providing valuable insights into the genetic basis of reproductive traits in goats.
Da Feng, Siyi Hu, Jian Ma et al.· Animal bioscience· 0 citations
Goats (Capra hircus) are among the world’s most important livestock, providing milk, meat, and fiber across diverse agro-ecological zones. Traditional breeding relying on pedigree-based estimated breeding values (EBVs) has driven steady genetic progress but is constrained by long generation intervals and limited accuracy for sex-limited or difficult-to-measure traits. High-throughput single nucleotide polymorphism (SNP) chips and genomic selection (GS) have transformed goat breeding by enabling early, accurate selection independent of phenotypic records. This review synthesizes the development of goat SNP chip platforms from the foundational 52 K GoatSNP50 BeadChip through high-density solid-phase arrays and low-cost liquid-phase capture panels, with emphasis on their relative performance, cost-effectiveness, imputation potential, and suitability for different breeding systems. In addition to genomic selection (GS), genome-wide association studies (GWAS), and genetic diversity assessment, we also discuss candidate-gene selection and marker-assisted selection (MAS) as practical intermediate approaches that remain relevant in many goat breeding programs. GS has achieved genomic estimated breeding value (GEBV) prediction accuracies of 0.35–0.79 for key production traits across multiple countries and breeds. GWAS has identified candidate genes for milk composition (DGAT1, CSN1S1), growth (PLAG1, HMGA2), reproduction (BMPR1B, GDF9), and fiber quality (KRT, KRTAP families). We compare GS with traditional BLUP-based approaches, assess economic benefits, and discuss key challenges including reference population construction, genotype imputation, inbreeding management via Optimum Contribution Selection (OCS), and multi-omics integration. Future directions include customized chip design, AI-assisted genomic prediction, climate adaptation breeding, and CRISPR/Cas9 gene editing for precision improvement.
Ting-Chieh Kang, Hisn-Hung Lin, Kai-Fei Tseng et al.· Frontiers in Veterinary Scie...· 0 citations
This narrative review synthesizes major advances in sheep genetic mapping, functional genomics, and GS relevant to economically important traits to provide researchers, breeders, and students with a balanced, evidence-based resource to guide future genomic improvements in sustainable sheep production.
Mostafa Ghaderi-Zefrehei, Effat Nasre Esfahani, Hassan Amini Pozveh et al.· Frontiers in Genetics· 0 citations