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The ecotype population of goats (Capra hircus) was created by long‐term artificial selection and natural adaptation. Mile red‐bone goat is an indigenous breed with visible red bones, and its special bone structure has received extensive attention. This study aimed to identify genetic variants and candidate genes associated with specific bone phenotypes using next‐generation sequencing technology (NGS). The results revealed that 31,828,206 single nucleotide polymorphisms (SNPs) were obtained from 72 goats (20 Mile red‐bone goats and 52 common goats) by NGS. A total of 100 candidate genes were identified on the basis top 1% window interaction from nucleotide diversity (π), π ratio (π A/π B), and pairwise fixation index (F ST). Exactly 77 known signaling pathways were enriched. Specifically, three coding genes (NMNAT2, LOC102172983, and PNLIP) were annotated in the vitamin metabolism signaling pathways, and NCF2 was annotated to the osteoclast (OC) differentiation pathway. Furthermore, 5862 reliable copy number variations (CNVs) were obtained, and 14 and 24 genes were annotated with the top 1‰ CNV based on F ST (>0.490) and V ST (>0.527), respectively. Several pathways related to bone development and metabolism of exogenous substances in vivo, including calcium signaling pathway, OC differentiation, and glycerophospholipid metabolism, were annotated. Specifically, six genes from 19 candidate CNVs, which were obtained by interaction of the top 1‰ CNVs with F ST and V ST, were annotated to mucin‐type O‐glycan biosynthesis and metabolic pathways. Briefly, the results implied that pseudopurpurin and specific genetic variants work together to contribute to the red‐bone color and specific bone structure of Mile red‐bone goat. This study is helpful to understanding the genetic basis of the unique bone phenotype of Mile red‐bone goats., Mile red‐bone goat is an indigenous breed with visible red bones and special bone structure has received extensive attention. The aim of this study was to identify genetic variants and candidate genes associated with specific bone phenotypes using next‐generation sequence technology (NGS). This study is helpful to understanding the genetic basis of unique bone phenotype of Mile red‐bone goats.

As one of the best-known commercial goat breeds in the world, Boer goat has undergone long-term artificial selection for nearly 100 years, and its excellent growth rate and meat production performance have attracted considerable worldwide attention. Herein, we used single nucleotide polymorphisms (SNPs) called from the whole-genome sequencing data of 46 Australian Boer goats to detect polymorphisms and identify genomic regions related to muscle development in comparison with those of 81 non-specialized meat goat individuals from Europe, Africa, and Asia. A total of 13 795 202 SNPs were identified, and the whole-genome selective signal screen with a π ratio of nucleotide diversity (πcase /πcontrol ) and pairwise fixation index (FST ) was analyzed. Finally, we identified 1741 candidate selective windows based on the top 5% threshold of both parameters; here, 449 candidate genes were only found in 727 of these regions. A total of 433 genes out of the 449 genes obtained were annotated to 2729 gene ontology terms, of which 51 were directly linked to muscle development (e.g., muscle organ development, muscle cell differentiation) by 30 candidate genes (e.g., JAK2, KCNQ1, PDE5A, PDLIM5, TBX5). In addition, 246 signaling pathways were annotated by 178 genes, and two pathways related to muscle contraction, including vascular smooth muscle contraction (ADCY7, PRKCB, PLA2G4E, ROCK2) and cardiac muscle contraction (CACNA2D3, CASQ2, COX6B1), were identified. The results could improve the current understanding of the genetic effects of artificial selection on the muscle development of goat. More importantly, this study provides valuable candidate genes for future breeding of goats.

This study compared and analyzed the genetic diversity and population structure of exon 2 of the DQB1 gene and 13 autosomal neutral microsatellite markers from 14 Chinese goat breeds to explore the potential evolutionary mechanism of the major histocompatibility complex (MHC). A total of 287 haplotypes were constructed from MHC-DQB1 exon 2 from 14 populations, and 82 nucleotide polymorphic sites (SNPs, 31.78%) and 172 heterozygous individuals (79.12%) were identified. The FST values of the microsatellites and MHC-DQB ranged between 0.01831–0.26907 and 0.00892–0.38871, respectively. Furthermore, 14 goat populations showed rich genetic diversity in the microsatellite loci and MHC-DQB1 exon 2. However, the population structure and phylogenetic relationship represented by the two markers were different. Positive selection and Tajima’s D test results showed the occurrence of a diversified selection mechanism, which was primarily based on a positive and balancing selection in goat DQB. This study also found that the DQB sequences of bovines exhibited trans-species polymorphism (TSP) among species and families. In brief, this study indicated that positive and balancing selection played a major role in maintaining the genetic diversity of DQB, and TSP of MHC in bovines was common, which enhanced the understanding of the MHC evolution.

Background:Polled intersex syndrome (PIS) leads to reproductive disorders in goats and exerts a heavy influence on goat breeding. Since 2001, the core variant of an 11.7 kb deletion at ~129 Mb on chromosome 1 (CHI1) has been widely used as a genetic diagnostic criterion. In 2020, a ~0.48 Mb insertion within the PIS deletion was identified by sequencing in XX intersex goats. However, the suitability of this variation for the diagnosis of intersex goats worldwide and its further molecular genetic mechanism need to be clarified.Results:The whole-genome selective sweep of intersex goats from China was performed with whole-genome next-generation sequencing technology for large sample populations and a case–control study on interbreeds. A series of candidate genes related to the goat intersexuality phenotype were found. We further confirmed that a ~0.48 Mb duplicated fragment (includingERGandKCNJ15) downstream of the ~20 Mb PIS region was reversely inserted into the PIS locus in intersex Chinese goats and was consistent with that in European Saanen and Valais black-necked goats. High-throughput chromosome conformation capture (Hi-C) technology was then used to compare the 3D structures of the PIS variant neighborhood in CHI1 between intersex and non-intersex goats. A newly found structure was validated as an intrachromosomal rearrangement. This inserted duplication changed the original spatial structure of goat CHI1 and caused the appearance of several specific loop structures in the adjacent ~20 kb downstream region ofFOXL2.Conclusions:Results suggested that the novel complex PIS variant genome was sufficient as a broad-spectrum clinical diagnostic marker of XX intersexuality in goats from Europe and China. A series of private dense loop structures caused by segment insertion into the PIS deletion might affect the expression ofFOXL2or other neighboring novel candidate genes. However, these structures require further in-depth molecular biological experimental verification. In general, this study provided new insights for future research on the molecular genetic mechanism underlying female-to-male sex reversal in goats.

The objective of the present study was to perform a genome-wide association study (GWAS) for growth curve parameters using nonlinear models that fit original weight&ndash, age records. In this study, data from 808 Chinese Simmental beef cattle that were weighed at 0, 6, 12, and 18 months of age were used to fit the growth curve. The Gompertz model showed the highest coefficient of determination (R2 = 0.954). The parameters&rsquo, mature body weight (A), time-scale parameter (b), and maturity rate (K) were treated as phenotypes for single-trait GWAS and multi-trait GWAS. In total, 9, 49, and 7 significant SNPs associated with A, b, and K were identified by single-trait GWAS, 22 significant single nucleotide polymorphisms (SNPs) were identified by multi-trait GWAS. Among them, we observed several candidate genes, including PLIN3, KCNS3, TMCO1, PRKAG3, ANGPTL2, IGF-1, SHISA9, and STK3, which were previously reported to associate with growth and development. Further research for these candidate genes may be useful for exploring the full genetic architecture underlying growth and development traits in livestock.

Background: Heat stress in domestic animals has become a major limit factor for livestock production in tropical and subtropical regions. These traits that adapt to torrid environment are important in livestock breeding.Methods: In this study, we identified and genotyped six Single nucleotide polymorphism for the CDC37, AHSA1 and STIP1 gene in the Droughtmaster, Angus and Simmental cattle breeds using the SNaPshot Multiplex system. Result: Result of pair-wise differences (FST) revealed three SNP locus (CDC37-6 (A16154247/G), CDC37-7 (C16157867/G), AHSA1-10 (G89722567/A) were significantly different in the Droughtmaster population than Angus and Simmental cattle breeds. Moreover, it was found that CDC37-7 (C16157867/G) locus deviated from Hardy-Weinberg equilibrium, suggesting that the CDC37-7 (C16157867/G) genes have been influenced by the selective breeding of the Droughtmaster breed. Therefore, CDC37-7 (C16157867/G) locus could be used as a marker-assisted candidate gene locus of heat tolerance. This study provides valuable information, concerning marker-assisted selection in the breeding of heat stress resistant cattle.

The genetic diversity and population structures of five Chongqing local chicken populations were investigated using by 24 microsatellite markers. Results revealed that the mean number of alleles (NA) ranged from 7.08 (Daninghe chicken, DN) to 8.46 (Nanchuan chicken, NC). The highest observed heterozygosity (HO) and expected heterozygosity (HE) were observed in DN (HO = 0.7252; HE = 0.7409) and the lowest HO and HE were observed in XS (Xiushan native chicken [XS], HO = 0.5910 and HE = 0.6697). The inbreeding coefficient (FIS) within population ranged from 0.022 (DN) to 0.119 (XS). Among the 24 microsatellite markers, four loci (MCW0111, MCW0016, ADL0278, and MCW0104) deviated from the Hardy–Weinberg equilibrium in all the studied populations. The results of population polygenetic analysis based on Nei’s genetic distance and STRUCTURE software showed that the clustering of the five populations was incomplete consistent with geographical distribution. Moreover, a large number of gene flows were widespread among different populations, suggesting that genetic material exchanges occurred due to human activities and migration which was also verified by PCoA. In summary, this study preliminarily showed that Chongqing local chicken populations had rich genetic diversity and remarkable genetic divergence, but still high risk in conversion. These findings would be useful to the management of conservation strategies and the utilization of local chicken populations in further.

Background: Myostatin (MSTN) is a highly conserved protein that acts as a negative regulator of skeletal muscle growth. MSTN gene is closely associated with multiple biological functions and its mutations are directly linked to muscle development in different species. Loss of MSTN functionality causes the phenotype to appear in the form of ‘double musculature’, among others in cattle, sheep and house mice.Methods: The mixed DNA pool of Boer and Dazu black goats to sequence MSTN coding and noncoding regions. Snapshot typing technology was used to analyse three goat production types, namely, Boer (meat goats), Nubian (breast and meat dual-use goat), Dazu black (local breeds) and Youzhou black goats (local breeds). Polymorphic loci in MSTN were used from four goat populations to construct haplotypes and calculate haplotype frequency distribution through NETWORK and MEGA to construct a phylogenetic tree and visualize phylogenetic relationship.Result: From these populations, 18 haplotypes were constructed using 20 polymorphic loci. Phylogenetic analysis revealed a significant difference in the haplotype distribution of MSTN in different goat production types. The 18 haplotypes were divided into two clusters. The haplotypes carried by the Boer goat belonged to Cluster I and those carried by the Nubian goat and two local goat breeds belonged to both clusters. Chinese local goats and complex production goats carried more haplotypes of MSTN and had a richer genetic diversity than other production types did. Moreover, local and complex production goats had high-frequency haplotypes of the MSTN of meat goats and had high potential for breeding.

Droughtmaster is a tropical breed of beef cattle that can survive in hot climates and easily adapt to torrid environments. These traits are important in livestock breeding. In this study, we genotyped five single-nucleotide polymorphisms (SNPs) of the AHSA2 gene from 190 cattle belonging to three different breeds (Droughtmaster, Angus and Simmental) by using snapshot technology. This work aimed to identify the valuable molecular marker of heat resistance in cattle. Results showed that Droughtmaster exhibited higher expected heterozygosity and polymorphic information content compared with the two other breeds. The AHSA2-1 locus deviated from the Hardy-Weinberg equilibrium in the Droughtmaster breed (P < 0.05). Two SNPs in Droughtmaster diverged significantly from Angus and Simmental. The SNPs were identified as AHSA2-3 and AHSA2-4, which were closely linked to the three breeds based on pair-wise FST. AHSA2-4 involved a missense mutation. In summary, the GG genotypes in AHSA2-3 and AHSA2-4 may be candidate genotypes associated with heat resistance traits and may serve as valuable genetic markers for breeding of heat-tolerant beef cattle in the future.

Major histocompatibility complex (MHC) genes are critical for disease resistance or susceptibility responsible for host-pathogen interactions determined mainly by extensive polymorphisms in the MHC genes. Here, we examined the diversity and phylogenetic pattern of MHC haplotypes reconstructed using three MHC-linked microsatellite markers in 55 populations of five Bovidae species and compared them with those based on neutral autosomal microsatellite markers (NAMs). Three-hundred-and-forty MHC haplotypes were identified in 1453 Bovidae individuals, suggesting significantly higher polymorphism and heterozygosity compared with those based on NAMs. The ambitious boundaries in population differentiation (phylogenetic network, pairwise FST and STRUCTURE analyses) within and between species assessed using the MHC haplotypes were different from those revealed by NAMs associated closely with speciation, geographical distribution, domestication and management histories. In addition, the mean FST was significantly correlated negatively with the number of observed alleles (NA), observed (HO) and expected (HE) heterozygosity and polymorphism information content (PIC) (P 0.05) between the MHC haplotype and NAMs datasets. Analysis of molecular variance (AMOVA) revealed a lower percentage of total variance (PTV) between species/groups based on the MHC-linked microsatellites than NAMs. Therefore, it was inferred that individuals within populations accumulated as many MHC variants as possible to increase their heterozygosity and thus the survival rate of their affiliated populations and species, which eventually reduced population differentiation and thereby complicated their classification and phylogenetic relationship inference. In summary, host-pathogen coevolution and heterozygote advantage, rather than demographic history, act as key driving forces shaping the MHC diversity within the populations and determining the interspecific MHC diversity.

The Tianzhu white yak, a domestic yak indigenous to the Qilian Mountains, migrated inland from the Qinghai-Tibet Plateau. Specific ecological and long-term artificial selection influenced the evolution of its pure white coat and physiological characteristics. Therefore, it is not only a natural population that represents a genomic selective region of environmental adaptability but is also an animal model for studying the pigmentation of the yak coat. A total of 24 261 829 variants, including 22 445 252 SNPs, were obtained from 29 yaks by genome-wide re-sequencing. According to the results of a selective sweep analysis of Tianzhu white yak in comparison to Tibetan yaks, nine candidate genes under selection in Tianzhu white yak were identified by combining π, Tajima's D, πA/πB and FST statistics, with threshold standards of 5%. These genes include PDCD1, NUP210, ABCG8, NEU4, LOC102287650, D2HGDH, COL4A1, RTP5 and HDAC11. Five of the nine genes were classified into 12 molecular signaling pathways, and most of these signaling pathways are involved in environmental information processing, organismal systems and metabolism. A majority of these genes has not been implicated in previous studies of yak coat color and high-altitude animals. Our findings are helpful not only for explaining the molecular mechanism of yak coat pigmentation but also for exploring the genetic changes in Tianzhu white yak due to environmental adaptation.

Sex reversal has been studied extensively in vertebrate species, particularly in domestic goats, because polled intersex syndrome (PIS) has seriously affected their production efficiency. In the present study, we used histopathologically diagnosed cases of PIS to identify correlated genomic regions and variants using representative selection signatures and performed GWAS using Restriction-Site Associated Resequencing DNA. We identified 171 single-nucleotide polymorphisms (SNPs) that may have contributed to this phenotype, and 53 SNPs were determined to be located in coding regions using a general linear model. The transcriptome data sets of differentially expressed genes (DEGs) in the pituitary tissues of intersexual and nonintersexual goats were examined using high-throughput technology. A total of 10,063 DEGs and 337 long noncoding RNAs were identified. The DEGs were clustered into 56 GO categories and determined to be significantly enriched in 53 signaling pathways by KEGG analysis. In addition, according to qPCR results, PSPO2 and FSH were significantly more highly expressed in sexually mature pituitary tissues of intersexual goats compared to healthy controls (nonintersexual). These results demonstrate that certain novel potential genomic regions may be responsible for intersexual goats, and the transcriptome data indicate that the regulation of various physiological systems is involved in intersexual goat development. Therefore, these results provide helpful data for understanding the molecular mechanisms of intersex syndrome in goats. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13205-019-1612-0) contains supplementary material, which is available to authorized users.