Analysis of genetic diversity and selection signals in Chaling cattle of southern China using whole-genome scan.

China has diversified resources of indigenous cattle, which are classified into Northern, Central, and Southern groups according to their geographical distribution. Chaling cattle belong to Southern group. This breed is famous for the production of good quality meat with elite meat grades. To analyze the genetic diversity of Chaling cattle, 20 samples were sequenced using whole-genome resequencing technology, along with 138 published whole-genome sequencing data of Indian indicine cattle, Chinese indicine cattle, East Asian taurine cattle, Eurasian taurine cattle, and European taurine cattle as control. It was found that Chaling cattle originated from Chinese indicine cattle. The genetic diversity of Chaling cattle is higher than that of Indian indicine cattle, East Asian taurine cattle, Eurasian taurine cattle, and European taurine cattle, but lower than that of Chinese indicine cattle and Xiangxi cattle. Annotating the selection signals obtained by composite likelihood ratio, θπ, F , π-ratio, and XP-EHH methods, several genes associated with immunity, heat tolerance, reproduction, growth, and meat quality showed strong selection signals. In general, this study provides a theoretical basis for analyzing the genetic mechanism of Chaling cattle with excellent adaptability, rough feeding tolerance, good immune performance, and good meat quality. This work lays a foundation for genetic breeding of Chaling cattle in future.

Li S ，Lei H ，Li J ，Sun A ，Ahmed Z ，Duan H ，Chen L ，Zhang B ，Lei C ，Yi K ... -  《-》

Whole-Genome Resequencing of Xiangxi Cattle Identifies Genomic Diversity and Selection Signatures.

Understanding the genetic diversity in Xiangxi cattle may facilitate our efforts toward further breeding programs. Here we compared 23 Xiangxi cattle with 78 published genomes of 6 worldwide representative breeds to characterize the genomic variations of Xiangxi cattle. Based on clustering models in population structure analysis, we displayed that Xiangxi cattle had a mutual genome ancestor with Chinese indicine, Indian indicine, and East Asian taurine. Population genetic diversity was analyzed by four methods (nucleotide diversity, inbreeding coefficient, linkage disequilibrium decay and runs of homozygosity), and we found that Xiangxi cattle had higher genomic diversity and weaker artificial selection than commercial breed cattle. Using four testing methods (θπ, CLR, , and XP-EHH), we explored positive selection regions harboring genes in Xiangxi cattle, which were related to reproduction, growth, meat quality, heat tolerance, and immune response. Our findings revealed the extent of sequence variation in Xiangxi cattle at the genome-wide level. All of our fruitful results can bring about a valuable genomic resource for genetic studies and breed protection in the future.

Luo X ，Li J ，Xiao C ，Sun L ，Xiang W ，Chen N ，Lei C ，Lei H ，Long Y ，Long T ，Suolang Q ，Yi K ... -  《Frontiers in Genetics》

Assessing genomic diversity and signatures of selection in Jiaxian Red cattle using whole-genome sequencing data.

Native cattle breeds are an important source of genetic variation because they might carry alleles that enable them to adapt to local environment and tough feeding conditions. Jiaxian Red, a Chinese native cattle breed, is reported to have originated from crossbreeding between taurine and indicine cattle; their history as a draft and meat animal dates back at least 30 years. Using whole-genome sequencing (WGS) data of 30 animals from the core breeding farm, we investigated the genetic diversity, population structure and genomic regions under selection of Jiaxian Red cattle. Furthermore, we used 131 published genomes of world-wide cattle to characterize the genomic variation of Jiaxian Red cattle. The population structure analysis revealed that Jiaxian Red cattle harboured the ancestry with East Asian taurine (0.493), Chinese indicine (0.379), European taurine (0.095) and Indian indicine (0.033). Three methods (nucleotide diversity, linkage disequilibrium decay and runs of homozygosity) implied the relatively high genomic diversity in Jiaxian Red cattle. We used θπ, CLR, F and XP-EHH methods to look for the candidate signatures of positive selection in Jiaxian Red cattle. A total number of 171 (θπ and CLR) and 17 (F and XP-EHH) shared genes were identified using different detection strategies. Functional annotation analysis revealed that these genes are potentially responsible for growth and feed efficiency (CCSER1), meat quality traits (ROCK2, PPP1R12A, CYB5R4, EYA3, PHACTR1), fertility (RFX4, SRD5A2) and immune system response (SLAMF1, CD84 and SLAMF6). We provide a comprehensive overview of sequence variations in Jiaxian Red cattle genomes. Selection signatures were detected in genomic regions that are possibly related to economically important traits in Jiaxian Red cattle. We observed a high level of genomic diversity and low inbreeding in Jiaxian Red cattle. These results provide a basis for further resource protection and breeding improvement of this breed.

Xia X ，Zhang S ，Zhang H ，Zhang Z ，Chen N ，Li Z ，Sun H ，Liu X ，Lyu S ，Wang X ，Li Z ，Yang P ，Xu J ，Ding X ，Shi Q ，Wang E ，Ru B ，Xu Z ，Lei C ，Chen H ，Huang Y ... -  《BMC GENOMICS》

Favored single nucleotide variants identified using whole genome Re-sequencing of Austrian and Chinese cattle breeds.

Cattle have been essential for the development of human civilization since their first domestication few thousand years ago. Since then, they have spread across vast geographic areas following human activities. Throughout generations, the cattle genome has been shaped with detectable signals induced by various evolutionary processes, such as natural and human selection processes and demographic events. Identifying such signals, called selection signatures, is one of the primary goals of population genetics. Previous studies used various selection signature methods and normalized the outputs score using specific windows, in kbp or based on the number of SNPs, to identify the candidate regions. The recent method of iSAFE claimed for high accuracy in pinpointing the candidate SNPs. In this study, we analyzed whole-genome resequencing (WGS) data of ten individuals from Austrian Fleckvieh () and fifty individuals from 14 Chinese indigenous breeds ( and admixed). Individual WGS reads were aligned to the cattle reference genome of ARS. UCD1.2 and subsequently undergone single nucleotide variants (SNVs) calling pipeline using GATK. Using these SNVs, we examined the population structure using principal component and admixture analysis. Then we refined selection signature candidates using the iSAFE program and compared it with the classical iHS approach. Additionally, we run Fst population differentiation from these two cattle groups. We found gradual changes of taurine in north China to admixed and indicine to the south. Based on the population structure and the number of individuals, we grouped samples to Fleckvieh, three Chinese taurines (Kazakh, Mongolian, Yanbian), admixed individuals (CHBI_Med), indicine individuals (CHBI_Low), and a combination of admixed and indicine (CHBI) for performing iSAFE and iHS tests. There were more significant SNVs identified using iSAFE than the iHS for the candidate of positive selection and more detectable signals in taurine than in indicine individuals. However, combining admixed and indicine individuals decreased the iSAFE signals. From both within-population tests, significant SNVs are linked to the olfactory receptors, production, reproduction, and temperament traits in taurine cattle, while heat and parasites tolerance in the admixed individuals. Fst test suggests similar patterns of population differentiation between Fleckvieh and three Chinese taurine breeds against CHBI. Nevertheless, there are genes shared only among the Chinese taurine, such as PAX5, affecting coat color, which might drive the differences between these yellowish coated breeds, and those in the greater Far East region.

Naji MM ，Jiang Y ，Utsunomiya YT ，Rosen BD ，Sölkner J ，Wang C ，Jiang L ，Zhang Q ，Zhang Y ，Ding X ，Mészáros G ... -  《Frontiers in Genetics》

Genetic Diversity and Selective Signature in Dabieshan Cattle Revealed by Whole-Genome Resequencing.

Dabieshan cattle are a typical breed of southern Chinese cattle that have the characteristics of muscularity, excellent meat quality and tolerance to temperature and humidity. Based on 148 whole-genome data, our analysis disclosed the ancestry components of Dabieshan cattle with Chinese indicine (0.857) and East Asian taurine (0.139). The Dabieshan genome demonstrated a higher genomic diversity compared with the other eight populations, supported by the observed nucleotide diversity, linkage disequilibrium decay and runs of homozygosity. The candidate genes were detected by a selective sweep, which might relate to the fertility (, ), feed efficiency (), immune response (, , ), heat resistance (, , ), fat deposition () and the coat color (). We also identified the "East Asian taurine-like" segments in Dabieshan cattle, which might contribute to meat quality traits. The results revealed by the unique and valuable genomic data can build a foundation for the genetic improvement and conservation of genetic resources for indigenous cattle breeds.

Guan X ，Zhao S ，Xiang W ，Jin H ，Chen N ，Lei C ，Jia Y ，Xu L ... -  《Biology-Basel》