The reproductive ability of sows is the principle of continuous and efficient production, based on such traits as the number of piglets, the total number of parities, and the period of economic use. Currently, SNPs associated with the TNB and NBA are presented in the PigQTLdb. The aim of this work was the assessment of the SNP effects on the litter traits in Large White (LW, n = 502) and Landrace (LN, n = 432) sow breeds in a farm in Russia. 9 SNPs (SNP_1: rs80956812; SNP_2: rs81471381; SNP_3: rs80891106; SNP_4: rs81399474; SNP_5: rs81421148; SNP_6: rs81242222; SNP_7: rs81319839; SNP_8: rs81312912; SNP_9: rs80962240) were selected for the study. Associative analysis was performed using the GLM procedure in R version 3.5.1. The analysis of reproductive traits was carried out according to the results of the first parity, the second and subsequent parities, and totals for lifetime of sows. The significant effect on litter traits in LW was determined for SNP rs80956812, SNP rs81471381, SNP rs81421148, and SNP rs81399474. The significant effect on litter traits in LN was determined for SNP rs81421148 and SNP rs81319839. AKT3 gene was identified as perspective candidate gene, whose biological functions, as well as the results obtained in our work and in other studies, indicate its potential role in the reproductive process regulation in pigs. In general, the data obtained help to explain the genetic mechanisms of reproductive traits.

The aim of this study was to identify genetic variants and pathways associated with the total number of piglets born and to investigate the potential negative consequences of the intensive selection for reproductive traits, particularly the formation of bumps on the legs of pigs. We used genome-wide association analysis and methods for identifying selection signatures. As a result, 47 SNPs were identified, localized in genes that play a significant role during sow pregnancy. These genes are involved in follicle growth and development (SGC), early embryonic development (CCDC3, LRRC8C, LRFN3, TNFRSF19), endometrial receptivity and implantation (NEBL), placentation, and embryonic development (ESRRG, GHRHR, TUSC3, NBAS). Several genes are associated with disorders of the nervous system and brain development (BCL11B, CDNF, ULK4, CC2D2A, KCNK2). Additionally, six SNPs are associated with the formation of bumps on the legs of pigs. These variants include intronic variants in the CCDC3, ULK4, and MINDY4 genes, as well as intergenic variants, regulatory region variants, and variants in the exons of non-coding transcripts. The results suggest important biological pathways and genetic variants associated with sow fertility and highlight the potential negative impacts on the health and physical condition of pigs.

The study of the local sheep breeds’ genetic architecture is an important step on the way to preserve their gene pool. The aim of our work was to identify candidate genes associated with the live weight trait in adult southern meat breed sheep. This breed has high productivity, but is under threat of a critical decrease in genetic diversity due to a small number. The live weight of farm animals is one of the key breeding indicators. This quantitative trait is polygenic and breed specific as it has been shown by a number of authors. Animals were genotyped on the Illumina Ovine SNP50 Genotyping Bead Chip assay using standard procedures. Results in quality control, statistics and visualization were carried out in Rstudio 2023.03.0 and plink1.9. Genotyped animals were divided into two groups according to the case/control principle with differences in live weight between representatives of groups of 25–30 kg. Significant genetic variants were determined by the fixation indices method. Further analysis of significant variants (in intron positions) was performed in Ensembl genomic browser and revealed candidate genes localized in chromosomes 5, 6, 12, 20. The statistical analysis of live mass showed significant differences of the studied trait in different genotypes on four genes. The candidate genes identified can be recommended for using as genetic markers, their study could improve the productivity of southern meat sheep breed and help to preserve its gene pool.

The paper presents the results of search for candidate genes for live weight in sheep of the southern meat breed. The sample of 48 ewes weighed at the age of 24 months and older was genotyped on an Ovine SNP 50 Genotyping BeadChip array. Using the method of fixation indices (F_ST), we detected 55 polymorphisms associated with live weight. Ten SNPs with the highest F_ST value were selected to check the effect on the trait under investigation. All the candidate genes showed the association with the live weight trait. It is interesting to note that, in the NDFIP1 gene, two significant SNPs with a high F_ST value were detected.