Copy Number Variation Analysis Revealed the Evolutionary Difference between Chinese Indigenous Pigs and Asian Wild Boars

Genome-wide CNV analysis reveals candidate genes associated with milk production traits in water buffalo (Bubalus bubalis)

Buffaloes are vital contributors to the global dairy industry. Understanding the genetic basis of milk production traits in buffalo populations is essential for breeding programs and improving productivity. In this study, we conducted whole-genome resequencing on 387 buffalo genomes from 29 diverse Asian breeds, including 132 river buffaloes, 129 swamp buffaloes, and 126 crossbred buffaloes. We identified 36,548 copy number variant (CNVs) spanning 133.29 Mb of the buffalo genome, resulting in 2,100 copy number variant regions (CNVRs), with 1,993 shared CNVRs being found within the studied buffalo types. Analyzing CNVRs highlighted distinct genetic differentiation between river and swamp buffalo subspecies, verified by evolutionary tree and principal component analyses. Admixture analysis grouped buffaloes into river and swamp categories, with crossbred buffaloes displaying mixed ancestry. To identify candidate genes associated with milk production traits, we employed 3 approaches. First, we used Vst-based population differentiation, revealing 11 genes within CNVRs that exhibited significant divergence between different buffalo breeds, including genes linked to milk production traits. Second, expression quantitative loci (eQTL) analysis revealed differential expression of CNVR-driven genes (DECGs) associated with milk production traits. Notably, known milk production-related genes were among these DECGs, validating their relevance. Last, a genome-wide association study (GWAS) identified 3 CNVRs significantly linked to peak milk yield. Our study provides comprehensive genomic insights into buffalo populations and identifies candidate genes associated with milk production traits. These findings facilitate genetic breeding programs aimed at increasing milk yield and improving quality in this economically important livestock species.

The Genetic Selection of HSPD1 and HSPE1 Reduce Inflammation of Liver and Spleen While Restraining the Growth and Development of Skeletal Muscle in Wuzhishan Pigs

Wuzhishan (WZS) pigs, which are minipigs native to Hainan Province in China, are characterized by strong resistance to extreme hot temperatures and humidity. The relationship between their immune response and growth still needs to be clarified. In this study, we used whole genome sequencing (WGS) to detect variations within 37 WZS pigs, 32 Large White (LW) pigs, and 22 Xiangxi black (XXB) pigs, and ~2.49 GB of SNPs were obtained. These data were combined with those of two other pig breeds, and it was found that most of the genes detected (354) were located within the distinct genetic regions between WZS pigs and LW pigs. The network that was constructed using these genes represented a center including 12 hub genes, five of which had structural variations (SVs) within their regulatory regions. Furthermore, RNA-seq and RT-qPCR data for 12 genes were primarily consistent in liver, spleen, and LDM tissues. Notably, the expression of HSPs (HSPD1 and HSPE1) was higher while that of most genes involved in the JAK3-STAT pathway were lower in liver tissue of WZS pigs, compared with LW pigs. This likely not only reduced inflammation-related immune response but also impaired their growth. Our findings demonstrated the role of HSPs in the connection between inflammation and growth rate, while also providing the fundamental genetic selection of the adaptability of WZS pigs.

Genomic signatures reveal selection in Chinese and European domesticated geese

The Swan goose and Greylag goose are species of geese native to East Asia and Europe, respectively, and are widely believed to be the ancestors of Chinese and European domesticated geese. The Yili goose (YL) and European domestic geese originated from the Greylag goose, but the history of domestication is unclear. In this study, we sequenced and analyzed the genome of the YL goose and the Hortobagy goose to combine with other previously sequenced goose populations for in-depth analysis. The population genetic variations in Stone geese, East Zhejiang White Geese, Taihu geese and Zi geese were also identified and compared. The results showed that admixture gene flow existed in the YL geese population, which was introgressed by Chinese geese, suggesting that gene flow events were frequent and widespread among domesticated geese. Further selected sweep analysis identified candidate genes and metabolic pathways that may be related to the differences in morphology. Several genes such as TGFBR3L, CMYA5, FOXD1, ARHGEF28 and SUCLG2 are associated with growth, reproduction and fertility traits. The results of this study will help to understand the genetic characteristics of domestic geese and the genes affecting important traits and provide a basis for the improved breed of domestic geese.