The origin of domestication genes in goats

Analysis of genetic diversity and selection signatures on the Zhashi Brown goat through whole genome sequencing data

The Zhashi Brown goat is native to Hengyang Municipality in Hunan Province in southern China and boasts a rich history. The goats exhibit exceptional traits, including heat and insect resistance, strong reproductive capabilities and superior meat production. Despite these merits, the currently limited population requires immediate conservation endeavors. In this study, we conducted whole-genome resequencing on 21 Zhashi Brown goats. Additionally, we performed a joint analysis using published whole-genome data from 119 goats, including Chengdu Brown goat, Matou goat, Wuxue goat, Xiangdong Black goat, Qaidam Cashmere goat, Ujumqin Cashmere goat and Shanbei Cashmere goat. The results revealed that the Zhashi Brown goat is genetically more pure than other Southern Chinese goat breeds. Furthermore, the genetic diversity (nucleotide diversity, linkage disequilibrium, runs of homozygosity and inbreeding coefficient) of the Zhashi Brown goat's genome is at a low level among the eight breeds, indicating the need for further conservation. Employing analytical methodologies such as composite likelihood ratio, nucleotide diversity, integrated haplotype score, the fixation index and cross-population extended haplotype homozygosity, we systematically scanned selective signals within the genomic landscape of Zhashi Brown goat. The outcomes underscore strong selection signals associated with genes implicated in immune response, heat tolerance, reproductive performance and meat quality. These findings make a significant contribution to our understanding of the genetics framework associated with adaptive traits in Zhashi Brown goat. Furthermore, this study explores the genetic diversity of the Zhashi Brown goat, which may contribute to the theoretical framework for conserving its genetic resources, while the identified trait-associated variations could inform future strategies to optimize selective breeding programs.

Revised phylogeny of mouflon based on expanded sampling of mitogenomes

Mouflons are flagship species of the Mediterranean islands where they persist. Once thought to be the remnants of a European wild sheep population, archaeology suggests they were introduced by humans to the islands of Cyprus in the Early Neolithic (~10,000 years ago) and later to Corsica and Sardinia. Their status as truly wild animals remains a subject of debate. To investigate the phylogenetic relationship between these island populations and other domestic and wild sheep from the Mediterranean region, we sequenced 50 mitogenomes of mouflons from Sardinia and Corsica, and modern and ancient Sardinian domestic sheep. A total of 68 additional publicly available mitogenomes were included in the comparative analysis and used to reconstruct the phylogeny of sheep and its closest wild relative, the mouflon (Ovis gmelini). Our study analyzed the evolutionary relationships within the C-E-X and haplogroup B clusters, showing that: a) Cyprus mouflons are more related to Anatolian and Iranian mouflons belonging to the wild haplogroup X, which seems to be basal to the domestic C and E haplogroups; b) Corsican and Sardinian mouflon arise from basal lineages associated with the early European expansion of domestic sheep. These results highlight the phylogenetic distinctiveness of the mouflon populations from the Mediterranean islands, suggesting a revision of their systematic classification and an update of the nomenclature for Sardinian and Corsican mouflons from the current status of subspecies of domestic sheep (Ovis aries musimon) to subspecies of their wild relatives (Ovis gmelini musimon) which would facilitate conservation efforts.

Genomic insights into the population history of fat-tailed sheep and identification of two mutations that contribute to fat tail adipogenesis

INTRODUCTION

Since their domestication, domestic sheep (Ovis aries) have been culturally and economically significant farming animals worldwide. Fat-tailed sheep serve as a unique genetic resource for understanding adipogenesis and adaptive evolution in livestock.

OBJECTIVES

Several genomic analyses have been conducted on various sheep breeds to elucidate the genome and regulation mechanism of the fat tail trait, prior genomic studies have failed to reconcile conflicting evidence about the genetic basis of tail morphology, particularly regarding the roles of PDGFD and BMP2.

METHODS

Here, we conducted whole-genome resequencing of 283 sheep, encompassing 66 domestic breeds and 5 wild ovine species, to investigate the domestication history and selection signatures of fat-tailed sheep. Additionally, we performed transcriptome sequencing on adipose tissue to identify differentially expressed genes and cellular assays to validate these results.

RESULTS

Demographic analysis revealed that domestic sheep descended from Asiatic mouflon and fat-tailed sheep began to diverge from thin-tailed sheep approximately 4.4-7.5 thousand years ago in East Asia. Chinese indigenous sheep were classified into Mongolian, Kazakh, Tibetan, and Yunnan populations. The Yunnan population may have experienced more recent genetic introgression from wild species, rather than an independent domestication event. Moreover, many potential regions associated with the fat-tailed phenotype (DDI1, PDGFD, and BMP2) were identified by selective sweep and genome-wide association analyses. Additionally, a fine-scale analysis of fat-tailed and thin-tailed sheep revealed two novel mutations: a G/A missense variant of PDGFD (Chr15: 3900312) and a C/T missense variant of BMP2 (Chr13: 48462350), both of which were significantly associated with tail adiposity. Functional validation demonstrated that mutant A-PDGFD significantly activated PFGFD expression and reduced fat deposition compared to wildtype. The C-BMP2 mutant activated BMP2 expression and promoted preadipocyte fat deposition.

CONCLUSION

Our study provides the first evidence that these genes jointly regulate fat tail development through complementary mechanisms: PDGFD promotes adipose expansion, whereas BMP2 modulates energy partitioning. These findings offer new insights into the evolutionary history of fat-tailed sheep and identify potential targets for precision breeding in small ruminants.

Whole genome sequencing revealed genetic structure, domestication, and selection of Chinese indigenous ducks

The genetic architecture and domestication history of Chinese indigenous ducks, particularly those with distinct traits like the Longsheng duck (LSD), are not well characterized. This study used whole-genome resequencing data from 540 ducks across 30 populations to explore the genetic diversity and structure of these ducks. Our findings suggest extensive interspecific hybridization between mallard and spot-billed duck. Comparing with other Chinese ducks, LSD is a distinct breed with moderate genetic diversity. Selective signal analysis identified several key genes impacting neural development, fat metabolism, immunity, and circadian rhythms like SLC25A20 and PER2. These genes showed strong selective pressures that parallelled other domestication processes. Additionally, EDNRB2 was identified as a potential gene influencing the unique coloration of LSD's plumage, bill, and webbed feet, associated with distinct mutations in non-coding regions. Comparative analysis with other indigenous breeds further pinpointed genes associated with LSD-specific traits, including plumage color, reproductive capabilities, and fat deposition, such as MITF, SPATA2, EIF2S2, PLIN3, ATP1B1, and CCDC80. Our findings clarify the population genetics of Chinese indigenous ducks. They also highlight key genes and mutations that shape the unique characteristics of LSD. These insights pave the way for further research into the genetic resources and domestication patterns of Chinese ducks.

Metabolome genome-wide association analyses identify a splice mutation in AADAT affects lysine degradation in duck skeletal muscle

Metabolites in skeletal muscles play an important role in their growth, development, immunity and other physiological activities. However, the genetic basis of metabolites in skeletal muscle remains poorly understood. Here, we identified 247 candidate divergent regions containing 905 protein-coding genes closely related to metabolic pathways, including lysine degradation and fatty acid biosynthesis. We then profiled 3,060 metabolites in 246 skeletal muscle samples from F2 segregating population generated by mallard×Pekin duck crosses using metabolomic approaches. We identified 2,044 significant metabolome-based GWAS signals and 21 candidate genes potentially modulating metabolite contents in skeletal muscle. Among them, the levels of 2-aminoadipic acid in skeletal muscle were significantly correlated with body weight and intramuscular fat content, determined by a 939-bp CR1 LINE insertion in AADAT. We further found that the CR1 LINE insertion most possibly led to a splice mutation in AADAT, resulting in the downregulation of the lysine degradation pathway in skeletal muscle. Moreover, intramuscular fat content and fatty acids biosynthesis pathway was significantly increased in individuals with CR1 LINE insertion. This study enhances our understanding of the genetic basis of skeletal muscle metabolic traits and promotes the efficient utilization of metabolite traits in the genetic improvement of animals.

Identification and expression profile analysis of circRNAs associated with goat uterus with different fecundity during estrous cycle

BACKGROUND

The Yunshang Black Goat, a distinguished meat goat breed native to China, is renowned for its superior reproductive capabilities. Despite this, there is considerable phenotypic variability within the breed. During the reproductive cycle, the uterus plays a pivotal role, with its functions evolving in line with the different stages of the cycle. This study focuses on the uterine tissues, including both the endometrium and myometrium, of Yunshang Black Goats with high fecundity (HF) and low fecundity (LF) during the proliferative (FP) and secretory (LP) phases of the estrous cycle. By examining these tissues, we aim to elucidate the underlying molecular and physiological mechanisms of the observed differences in reproductive success.

RESULTS

High-throughput sequencing was conducted, followed by bioinformatics analysis to identify the expression profiles of circRNAs. A total of 7,445 circRNAs were identified through the integration of findings from find_circ and CIRI2 software. Comparative analyses between the FPLF vs. FPHF and LPLF vs. LPHF revealed 149 differentially expressed (DE) circRNAs (94 up-regulated and 55 down-regulated) and 276 DE circRNAs (56 up-regulated and 220 down-regulated), respectively. The enrichment analysis indicated that the primary pathways involved were the Sphingolipid signaling pathway, MAPK signaling pathway, and GnRH signaling pathway, all of which are closely associated with cellular growth and development. Additionally, several key candidate genes were identified, such as FGF2 and MBTPS1. We also predicted a total of 281 miRNA-circRNA binding pairs, encompassing 263 circRNAs and 60 miRNAs, and simultaneously, 14 coding circRNAs were anticipated.

CONCLUSION

Based on the analysis, we have established the expression profiles of circRNAs during the follicular and luteal phases, respectively. Furthermore, using various analytical methods and data from high- and low-yield experimental control groups over different periods, we have identified multiple circRNAs that affect the high reproductive capacity of goats. Through enrichment analysis of the host genes of these circRNAs, we have discovered several key candidate genes. These findings provide fundamental data for the study of the molecular mechanisms underlying the fecundity of goats and pave the way for future genetic improvement strategies.

Genetic advancements and future directions in ruminant livestock breeding: from reference genomes to multiomics innovations

Ruminant livestock provide a rich source of products, such as meat, milk, and wool, and play a critical role in global food security and nutrition. Over the past few decades, genomic studies of ruminant livestock have provided valuable insights into their domestication and the genetic basis of economically important traits, facilitating the breeding of elite varieties. In this review, we summarize the main advancements for domestic ruminants in reference genome assemblies, population genomics, and the identification of functional genes or variants for phenotypic traits. These traits include meat and carcass quality, reproduction, milk production, feed efficiency, wool and cashmere yield, horn development, tail type, coat color, environmental adaptation, and disease resistance. Functional genomic research is entering a new era with the advancements of graphical pangenomics and telomere-to-telomere (T2T) gap-free genome assembly. These advancements promise to improve our understanding of domestication and the molecular mechanisms underlying economically important traits in ruminant livestock. Finally, we provide new perspectives and future directions for genomic research on ruminant genomes. We suggest how ever-increasing multiomics datasets will facilitate future studies and molecular breeding in livestock, including the potential to uncover novel genetic mechanisms underlying phenotypic traits, to enable more accurate genomic prediction models, and to accelerate genetic improvement programs.

Whole-genome variants resource of 298 Saanen dairy goats

The Saanen breeds are often used as terminal sires for hybridization and play an important role in the global dairy food industry. However, there is still a lack of genomics information on the Saanen dairy goats. Whole-genome sequencing offers a promising approach to identify genetic markers associated with economic traits and discover new candidate genes. This can effectively utilize genetic resources to accelerate breeding processes and improve lactation performance in Saanen dairy goats. In this study, we present the genomes of 298 Saanen dairy goats. Through rigorous sequencing and quality control, we achieved an average sequencing depth of 14.6X, with 92.3% of high-quality (Q30 > 90%) data and an average mapping ratio of 99.9%, indicating reliable results. By comparing our data to a reference genome of Saanen dairy goats, we identified14.59 million single nucleotide polymorphisms (SNPs) and 1.34 million insertions-deletions (InDels). This dataset significantly contributes to enriching public databases in dairy goats and provides valuable resources for studying genetic diversity, improving breeds, and developing new varieties.

Whole-Genome Sequencing-Based Population Genetic Analysis of Wild and Domestic Rabbit Breeds

The European rabbit exists in the wild and has several highly bred domesticated forms. There are well-separated wild European rabbit populations, and intensive breeding has resulted in various forms and utilizations. In this work, we aimed to carry out an extended WGS-based population genomics study on several wild European rabbit populations and selected breeds. Utilizing multiple methods, we showed that although domestic and wild populations were clearly separated, there was evidence of admixture between them in France and Hungary. The populations showed various levels of inbreeding, with one of the Hungarian subpopulations having excess runs of homozygosity. We identified numerous variants fixed in either domestic or wild animals, two of which were found to be fixed at different alleles in the two populations. Some putatively selected regions did not overlap with any known genes in the rabbit genome, suggesting some importance to these intergenic sites. The enrichment of selected regions in certain types of transcription factor binding sites suggests a possible role for these regulatory elements during domestication. In addition, the new high-coverage rabbit whole-genome sequences may provide helpful material for further population genetics analyses.

Metabolic pathways associated with Firmicutes prevalence in the gut of multiple livestock animals and humans

Dynamic interspecific interactions and environmental factors deeply impact the composition of microbiotic communities in the gut. These factors intertwined with the host's genetic background and social habits cooperate synergistically as a hidden force modulating the host's physiological and health determinants, with certain bacterial species being maintained from generation to generation. Firmicutes, one of the dominant bacterial phyla present across vertebrate classes, exhibits a wide range of functional capabilities and colonization strategies. While ecological scenarios involving microbial specialization and metabolic functions have been hypothesized, the specific mechanisms that sustain the persistence of its microbial taxa in a high diversity of hosts remain elusive. This study fills this gap by investigating the Firmicutes metabolic mechanisms contributing to their prevalence and heritability in the host gut on metagenomes-assembled bacterial genomes collected from 351 vertebrate samples, covering 18 food-producing animals and humans, specific breeds and closely-related species. We observed that taxa belonging to Acetivibrionaceae, Clostridiaceae, Lachnospiraceae, Ruminococcaceae, and the not well understood CAG-74 family were evolutionarily shared across all hosts. These prevalent taxa exhibit metabolic pathways significantly correlated with extra-host survival mechanisms, cell adhesion, colonization and host transmission, highlighted by sporulation, glycan biosynthesis, bile acid metabolism, and short-chain fatty acid encoded genes. Our findings provide a deeper understanding of the ecological foundations governing distinct transmission modes, effective colonization establishment, and maintenance of Firmicutes, offering new perspectives on both well-known and poorly characterized species.

Whole genome and transcriptome analyses in dairy goats identify genetic markers associated with high milk yield

Milk production is the most important economic trait of dairy goats and a key indicator for genetic improvement and breeding. However, milk yield is a complex phenotypic trait, and its genetic mechanisms are still not fully understood. This study focuses on dairy goats and non-dairy goats. By analyzing the population structure of these two groups, we found that there is a significant genetic distance between the populations of dairy goats and non-dairy goats. Using SNP and Indel analyses to identify selection signals, we identified several genes associated with milk production traits, including MPP7, PRPF6, DNAJC5, TPD52L2, HNF4G, LAMA3, FAM13A, and EPHA5. Through longitudinal GWAS of the milk production traits of 298 dairy goats, we discovered additional genes such as TRNAS-GGA-102, TTC39C, LAMA3, ANKRD29, NPC1, C24H18orf8, LOC108633789, RIOK3, TMEM241, CABLES1, LOC108633781, and RBBP8. Transcriptome sequencing of breast tissues at different lactation stages reveals dynamic LAMA3 expression changes. Three non-synonymous mutations in LAMA3 are identified, with the TT genotype at one site correlating significantly with average milk production in dairy goats. Our study discovered new genetic markers for improving dairy goat genetics and provided valuable insights into the genetic mechanisms underlying complex traits.

Whole-Genome Selective Scans Detect Genes Associated with Cashmere Traits and Climatic Adaptation in Cashmere Goats (Capra hircus) in China

Background: Cashmere, valued for its exceptional softness and warmth, is a major focus in goat breeding due to its high economic importance. However, the molecular mechanisms underlying cashmere production remain largely unknown, hindering efforts to optimize yield and quality. Additionally, domestic goats exhibit remarkable adaptability to diverse climates, ranging from arid northern regions to humid southern areas, yet the genetic basis for these adaptations is poorly understood. Exploring the genetic factors driving cashmere production and climatic adaptation could provide crucial insights into trait evolution and support the development of breeding strategies for improved productivity and resilience. Methods: We utilized whole-genome resequencing data from 157 samples representing 14 goat populations to analyze the genetic diversity between cashmere and non-cashmere breeds. Additionally, we conducted the tests of selective sweeps (i.e., pairwise FST, θπ and XP-EHH) for cashmere traits and genome-environment association analysis (i.e., XtX statistic), respectively. Results: We identified strong selective signatures in previous reports (e.g., AKT3, FOXP1, FGF5, TGFBR3) and novel genes (e.g., ZEB1, ZNRF3, MAPK8IP3, MAPK8IP2, AXIN1) associated with cashmere traits. Further gene annotation and KEGG analyses showed that these genes were identified to be the most probable genes accounting for the cashmere traits. Also, we detected some genes such as PDGFRB, PRDM8, SLC26A2, SCAMP1, EPHX1, CDC25A, and POLK that played critical roles in the adaptation of goats to local climate variation. Conclusions: Collectively, our results provide novel insights into the genetic mechanisms underlying the cashmere traits and climatic adaptation, and also identified new genetic markers for genetic improvement in goats.

Population structure, selection signal and introgression of gamecocks revealed by whole genome sequencing

BACKGROUND

As an important genetic resource of chickens, gamecock has unique morphological and behavioral characteristics such as large size, muscular development and strong aggression, making it a good model for studying muscle development and behavior patterns, as well as an excellent breeding material. Gamecocks are distributed worldwide, forming different breeds and strains. However, the single or multiple origin of global gamecocks has not been fully established and much remains unknown about genetic introgression events between gamecocks and other chickens. Therefore, in this study, based on whole genome data of gamecocks, Chinese indigenous chickens, commercial chickens and wild jungle fowls, we performed population structure analysis, selection signal analysis, and genomic introgression analysis of gamecocks.

RESULTS

The population structure analysis revealed that gamecocks have multiple origins. In addition, we used Fst, π-Ratio and XP-EHH methods to explore the candidate signatures of positive selection in gamecocks. A total number of fifteen shared candidate genes were identified using the three different detection strategies. Among these candidate genes, ETV1, DGKB, AGMO, MEOX2, ISPD and PLCB4 are related to the growth and muscle development, fighting performance and neurodevelopment of gamecocks. Furthermore, we detected the introgression event at the MYBPHL region from the Gallus sonneratii into Euramerican gamecocks and at the CPZ gene region from the Gallus gallus gallus into multiple gamecock populations, respectively, indicating the introgression from the wild junglefowl may impact the skeletal and muscle development as well as aggressive behavior of gamecocks.

CONCLUSIONS

In summary, we conducted a genome-wide exploration of gamecocks from multiple regions worldwide. Our analysis confirmed multiple origins of gamecocks and detected several candidate genes that are possibly related to important traits and characteristics in gamecocks. More importantly, this is the first study that has detected introgression events and genes from wild jungle fowls to gamecocks, which provides evidence of the wild jungle fowls contributing to the genetic diversity of gamecocks. Our findings offer new perspectives on the impact of introgression on gamecocks, and provide a basis for further resource conservation and utilization of gamecock, as well as provide excellent material for the genetic improvement of domestic chickens.

Hominin cognition: The null hypothesis

The target article explores material culture datasets from three African forager groups. After demonstrating that these modern, contemporary human populations would leave scant evidence of symbolic behaviour or material complexity, it cautioned against using material culture as a barometer for human cognition in the deep past. Twenty-one commentaries broadly support or expand these conclusions. A minority offer targeted demurrals, highlighting (1) the soundness of reasoning from absence; and questioning (2) the "cognitively modern" null; (3) the role of hunter-gatherer ethnography; and (4) the pertinence of the inferential issues identified in the target article. In synthesising these discussions, this reply addresses all four points of demurral in turn, and concludes that there is much to be gained from shifting our null assumptions and reconsidering the probabilistic inferential links between past material culture and cognition.

Complete Genomic Landscape Reveals Hidden Evolutionary History and Selection Signature in Asian Water Buffaloes (Bubalus bubalis)

To identify the genetic determinants of domestication and productivity of Asian water buffaloes (Bubalus bubalis), 470 genomes of domesticated river and swamp buffaloes along with their putative ancestors, the wild water buffaloes (Bubalus arnee) are sequenced and integrated. The swamp buffaloes inherit the morphology of the wild buffaloes. In contrast, most river buffaloes are unique in their morphology, but their genomes cluster with the wild buffaloes. The levels of genomic diversity in Italian river and Indonesian swamp buffaloes decrease at opposite extremes of their distribution range. Purifying selection prevented the accumulation of harmful loss-of-function variants in the Indonesian buffaloes. Genes that evolved rapidly (e.g., GKAP1) following differential selections in the river and swamp buffaloes are involved in their reproduction. Genes related to milk production (e.g., CSN2) and coat color (e.g., MC1R) underwent strong selections in the dairy river buffaloes via soft and hard selective sweeps, respectively. The selective sweeps and single-cell RNA-seq data revealed the luminal cells as the key cell type in response to artificial selection for milk production of the dairy buffaloes. These findings show how artificial selection has been driving the evolutionary divergence and genetic differentiation in morphology and productivity of Asian water buffaloes.

A comprehensive review of livestock development: insights into domestication, phylogenetics, diversity, and genomic advances

Livestock plays an essential role in sustaining human livelihoods, offering a diverse range of species integral to food security, economic stability, and cultural traditions. The domestication of livestock, which began over 10,000 years ago, has driven significant genetic changes in species such as cattle, buffaloes, sheep, goats, and pigs. Recent advancements in genomic technologies, including next-generation sequencing (NGS), genome-wide association studies (GWAS), and genomic selection, have dramatically enhanced our understanding of these genetic developments. This review brings together key research on the domestication process, phylogenetics, genetic diversity, and selection signatures within major livestock species. It emphasizes the importance of admixture studies and evolutionary forces like natural selection, genetic drift, and gene flow in shaping livestock populations. Additionally, the integration of machine learning with genomic data offers new perspectives on the functional roles of genes in adaptation and evolution. By exploring these genomic advancements, this review provides insights into genetic variation and evolutionary processes that could inform future approaches to improving livestock management and adaptation to environmental challenges, including climate change.

Telomere-to-telomere genome assembly of a male goat reveals variants associated with cashmere traits

A complete goat (Capra hircus) reference genome enhances analyses of genetic variation, thus providing insights into domestication and selection in goats and related species. Here, we assemble a telomere-to-telomere (T2T) gap-free genome (2.86 Gb) from a cashmere goat (T2T-goat1.0), including a Y chromosome of 20.96 Mb. With a base accuracy of >99.999%, T2T-goat1.0 corrects numerous genome-wide structural and base errors in previous assemblies and adds 288.5 Mb of previously unresolved regions and 446 newly assembled genes to the reference genome. We sequence the genomes of five representative goat breeds for PacBio reads, and use T2T-goat1.0 as a reference to identify a total of 63,417 structural variations (SVs) with up to 4711 (7.42%) in the previously unresolved regions. T2T-goat1.0 was applied in population analyses of global wild and domestic goats, which revealed 32,419 SVs and 25,397,794 SNPs, including 870 SVs and 545,026 SNPs in the previously unresolved regions. Also, our analyses reveal a set of selective variants and genes associated with domestication (e.g., NKG2D and ABCC4) and cashmere traits (e.g., ABCC4 and ASIP).

Deep Ancestral Introgressions between Ovine Species Shape Sheep Genomes via Argali-Mediated Gene Flow

Previous studies revealed extensive genetic introgression between Ovis species, which affects genetic adaptation and morphological traits. However, the exact evolutionary scenarios underlying the hybridization between sheep and allopatric wild relatives remain unknown. To address this problem, we here integrate the reference genomes of several ovine and caprine species: domestic sheep, argali, bighorn sheep, snow sheep, and domestic goats. Additionally, we use 856 whole genomes representing 169 domestic sheep populations and their six wild relatives: Asiatic mouflon, urial, argali, snow sheep, thinhorn sheep, and bighorn sheep. We implement a comprehensive set of analyses to test introgression among these species. We infer that the argali lineage originated ∼3.08 to 3.35 Mya and hybridized with the ancestor of Pachyceriforms (e.g. bighorn sheep and snow sheep) at ∼1.56 Mya. Previous studies showed apparent introgression from North American Pachyceriforms into the Bashibai sheep, a Chinese native sheep breed, despite of their wide geographic separation. We show here that, in fact, the apparent introgression from the Pachyceriforms into Bashibai can be explained by the old introgression from Pachyceriforms into argali and subsequent recent introgression from argali into Bashibai. Our results illustrate the challenges of estimating complex introgression histories and provide an example of how indirect and direct introgression can be distinguished.

Bronze Age cheese reveals human-Lactobacillus interactions over evolutionary history

Despite the long history of consumption of fermented dairy, little is known about how the fermented microbes were utilized and evolved over human history. Here, by retrieving ancient DNA of Bronze Age kefir cheese (∼3,500 years ago) from the Xiaohe cemetery, we explored past human-microbial interactions. Although it was previously suggested that kefir was spread from the Northern Caucasus to Europe and other regions, we found an additional spreading route of kefir from Xinjiang to inland East Asia. Over evolutionary history, the East Asian strains gained multiple gene clusters with defensive roles against environmental stressors, which can be a result of the adaptation of Lactobacillus strains to various environmental niches and human selection. Overall, our results highlight the role of past human activities in shaping the evolution of human-related microbes, and such insights can, in turn, provide a better understanding of past human behaviors.

Chromosome-level genome assembly of the cashmere goat

The goat, an early domesticated ruminant, is a reliable source of cashmere, meat and milk in global agricultural production. Despite this, the genome of cashmere-rich goats has yet to be characterized. Here, we assembled the nearly complete genome of a cashmere goat from a highly economically valuable Inner Mongolian Cashmere buck, utilizing a combination of PacBio HiFi, ONT ultra-long reads, and Hi-C technologies. The size of this genome is 2.76 Gb, with a contig N50 of 95.22 Mb. All assembled sequences were anchored onto 29 autosomes and both sex chromosomes, with only two gaps present on the X chromosome. We identified 1,333.29 Mb (48.26%) of repetitive sequences and predicted 22,480 protein-coding genes. Assembly quality assessment of the genome demonstrated that our assembled cashmere goat genome surpasses the continuity, completeness, and accuracy of other published goat genomes. Taken together, we provided the first cashmere goat assembly, bridging the gap in the genome of important economic breeds of domestic goats, and providing a valuable reference resource for goat genetics and genome research.

The goat pan-genome reveals patterns of gene loss during domestication

BACKGROUND

Unveiling genetic diversity features and understanding the genetic mechanisms of diverse goat phenotypes are pivotal in facilitating the preservation and utilization of these genetic resources. However, the total genetic diversity within a species can't be captured by the reference genome of a single individual. The pan-genome is a collection of all the DNA sequences that occur in a species, and it is expected to capture the total genomic diversity of the specific species.

RESULTS

We constructed a goat pan-genome using map-to-pan assemble based on 813 individuals, including 723 domestic goats and 90 samples from their wild relatives, which presented a broad regional and global representation. In total, 146 Mb sequences and 974 genes were identified as absent from the reference genome (ARS1.2; GCF_001704415.2). We identified 3,190 novel single nucleotide polymorphisms (SNPs) using the pan-genome analysis. These novel SNPs could properly reveal the population structure of domestic goats and their wild relatives. Presence/absence variation (PAV) analysis revealed gene loss and intense negative selection during domestication and improvement.

CONCLUSIONS

Our research highlights the importance of the goat pan-genome in capturing the missing genetic variations. It reveals the changes in genomic architecture during goat domestication and improvement, such as gene loss. This improves our understanding of the evolutionary and breeding history of goats.

A Mutation Losing an RBP-Binding Site in the LncRNA NORSF Transcript Influences Granulosa Cell Apoptosis and Sow Fertility

Sow fertility is an economically important quantitative trait. Hundreds of quantitative trait loci (QTLs) containing tens of thousands of potential candidate genes are excavated. However, among these genes, non-coding RNAs including long non-coding RNAs (lncRNAs) are often overlooked. Here, it is reported that NORSF is a novel causal lncRNA for sow fertility traits in QTLs. QTLs are characterized for sow fertility traits at the genome-wide level and identified 4,630 potential candidate lncRNAs, with 13 differentially expressed during sow follicular atresia. NORSF, a lncRNA that involved in sow granulosa cell (sGC) function, is identified as a candidate gene for sow fertility traits as a G to A transversion at 128 nt in its transcript is shown to be markedly associated with sow fertility traits. Mechanistically, after forming the RNA:dsDNA triplexes with the promoter of Caspase8, NORSF transcript with allele G binds to an RNA-binding protein (RBP) NR2C1 and recruits it to the promoter of Caspase8, to induce Caspase8 transcription in sGCs. Functionally, this leads to a loss of inducing effect of NORSF on sGC apoptosis by inactivating the death receptor-mediated apoptotic pathway. This study identified a novel causal lncRNA that can be used for the genetic improvement of sow fertility traits.

Chromosomal-level reference genome assembly of muskox (Ovibos moschatus) from Banks Island in the Canadian Arctic, a resource for conservation genomics

The muskox (Ovibos moschatus), an integral component and iconic symbol of arctic biocultural diversity, is under threat by rapid environmental disruptions from climate change. We report a chromosomal-level haploid genome assembly of a muskox from Banks Island in the Canadian Arctic Archipelago. The assembly has a contig N50 of 44.7 Mbp, a scaffold N50 of 112.3 Mbp, a complete representation (100%) of the BUSCO v5.2.2 set of 9225 mammalian marker genes and is anchored to the 24 chromosomes of the muskox. Tabulation of heterozygous single nucleotide variants in our specimen revealed a very low level of genetic diversity, which is consistent with recent reports of the muskox having the lowest genome-wide heterozygosity among the ungulates. While muskox populations are currently showing no overt signs of inbreeding depression, environmental disruptions are expected to strain the genomic resilience of the species. One notable impact of rapid climate change in the Arctic is the spread of emerging infectious and parasitic diseases in the muskox, as exemplified by the range expansion of muskox lungworms, and the recent fatal outbreaks of Erysipelothrix rhusiopathiae, a pathogen normally associated with domestic swine and poultry. As a genomics resource for conservation management of the muskox against existing and emerging disease modalities, we annotated the genes of the major histocompatibility complex on chromosome 2 and performed an initial assessment of the genetic diversity of this complex. This resource is further supported by the annotation of the principal genes of the innate immunity system, genes that are rapidly evolving and under positive selection in the muskox, genes associated with environmental adaptations, and the genes associated with socioeconomic benefits for Arctic communities such as wool (qiviut) attributes. These annotations will benefit muskox management and conservation.

Analysis of goat PPP6C mRNA profile, detection of genetic variations, and their associations with litter size

The Protein Phosphatase 6 Catalytic Subunit (PPP6C) is evolutionarily a conserved gene in eukaryotes known to play a significant role in mammalian reproduction. This study aimed to investigate expression patterns of PPP6C and explore its association with litter size in Shaanbei white cashmere (SBWC) goats. Initially, we determined the mRNA expression levels of PPP6C in both male and female goats across multiple tissues. The results showed that PPP6C mRNA was expressed in multiple tissues, with higher levels in the testis and fallopian tubes, suggesting its involvement in goat reproduction. Additionally, we identified a novel 19 bp InDel within the PPP6C gene in a population of 1030 SBWC goats, which exhibited polymorphism. Statistical analysis revealed a significant association between the19 bp InDel mutation and litter size (P < 0.05). Subsequent, bioinformatics analysis, including linkage disequilibrium (LD) block and selective scanning, highlighted the linkage tendency among most InDel loci did not stand out within B-8 block, there were still some InDel loci linked to the 19 bp within a relatively narrow region. Furthermore, comparative analysis with Bezoars, these selective signals all indicated that this gene was under higher selection pressure, implying that the 19 bp InDel locus within the PPP6C is potentially associated with domesticated traits, particularly in relation to litter size. The results of the present study suggest that the PPP6C is a vital candidate gene affecting prolificacy in goats, with implications for selective breeding programs for goat breeds.

Whole-genome resequencing reveals diversity and selective signals in the Wuxue goat

Animal genetic resources are crucial for ensuring global food security. However, in recent years, a noticeable decline in the genetic diversity of livestock has occurred worldwide. This decline is pronounced in developing countries, where the management of these resources is insufficient. In the current study, we performed whole genome sequencing for 20 Wuxue (WX) and five Guizhou White (GW) goats. Additionally, we utilized the published genomes of 131 samples representing five different goat breeds from various regions in China. We investigated and compared the genetic diversity and selection signatures of WX goats. Whole genome sequencing analysis of the WX and GW populations yielded 120 425 063 SNPs, which resided primarily in intergenic and intron regions. Population genetic structure revealed that WX exhibited genetic resemblance to GW, Chengdu Brown, and Jintang Black and significant differentiation from the other goat breeds. In addition, three methods (nucleotide diversity, linkage disequilibrium decay, and runs of homozygosity) showed moderate genetic diversity in WX goats. We used nucleotide diversity and composite likelihood ratio methods to identify within-breed signatures of positive selection in WX goats. A total of 369 genes were identified using both detection methods, including genes related to reproduction (GRID2, ZNF276, TCF25, and SPIRE2), growth (HMGA2 and GJA3), and immunity (IRF3 and SRSF3). Overall, this study explored the adaptability of WX goats, shedding light on their genetic richness and potential to thrive in challenges posed by climatic changes and diseases. Further investigations are warranted to harness these insights to enhance more efficient and sustainable goat breeding initiatives.

Investigating the footprint of post-domestication dispersal on the diversity of modern European, African and Asian goats

BACKGROUND

Goats were domesticated in the Fertile Crescent about 10,000 years before present (YBP) and subsequently spread across Eurasia and Africa. This dispersal is expected to generate a gradient of declining genetic diversity with increasing distance from the areas of early livestock management. Previous studies have reported the existence of such genetic cline in European goat populations, but they were based on a limited number of microsatellite markers. Here, we have analyzed data generated by the AdaptMap project and other studies. More specifically, we have used the geographic coordinates and estimates of the observed (Ho) and expected (He) heterozygosities of 1077 European, 1187 African and 617 Asian goats belonging to 38, 43 and 22 different breeds, respectively, to find out whether genetic diversity and distance to Ganj Dareh, a Neolithic settlement in western Iran for which evidence of an early management of domestic goats has been obtained, are significantly correlated.

RESULTS

Principal component and ADMIXTURE analyses revealed an incomplete regional differentiation of European breeds, but two genetic clusters representing Northern Europe and the British-Irish Isles were remarkably differentiated from the remaining European populations. In African breeds, we observed five main clusters: (1) North Africa, (2) West Africa, (3) East Africa, (4) South Africa, and (5) Madagascar. Regarding Asian breeds, three well differentiated West Asian, South Asian and East Asian groups were observed. For European and Asian goats, no strong evidence of significant correlations between Ho and He and distance to Ganj Dareh was found. In contrast, in African breeds we detected a significant gradient of diversity, which decreased with distance to Ganj Dareh.

CONCLUSIONS

The detection of a genetic cline associated with distance to the Ganj Dareh in African but not in European or Asian goat breeds might reflect differences in the post-domestication dispersal process and subsequent migratory movements associated with the management of caprine populations from these three continents.

Illuminating Genetic Diversity and Selection Signatures in Matou Goats through Whole-Genome Sequencing Analysis

(1) Background: Matou goats, native to Hunan and Hubei provinces in China, are renowned for their exceptional meat and skin quality. However, a comprehensive whole-genome-based exploration of the genetic architecture of this breed is scant in the literature. (2) Methods: To address this substantial gap, we used whole-genome sequences of 20 Matou goats and compared them with published genomic data of 133 goats of different breeds across China. This comprehensive investigation sought to assess genetic diversity, population structure, and the presence of genomic selection signals. (3) Results: The whole genome of Matou goat populations yielded a substantial catalog of over 19 million single nucleotide polymorphisms (SNPs), primarily distributed within intergenic and intron regions. The phylogenetic tree analysis revealed distinct clades corresponding to each goat population within the dataset. Notably, this analysis positioned Matou goats in a closer genetic affinity with Guizhou White goats, compared to other recognized goat breeds. This observation was corroborated by principal component analysis (PCA) and admixture analysis. Remarkably, Matou goats exhibited diminished genetic diversity and a notable degree of inbreeding, signifying a reduced effective population size. Moreover, the study employed five selective sweep detection methods (including PI, CLR, PI-Ratio, Fst, and XP-EHH) to screen top signal genes associated with critical biological functions, encompassing cardiomyocytes, immunity, coat color, and meat quality. (4) Conclusions: In conclusion, this study significantly advances our understanding of the current genetic landscape and evolutionary dynamics of Matou goats. These findings underscore the importance of concerted efforts in resource conservation and genetic enhancement for this invaluable breed.

Genetic diversity and population structure in five Inner Mongolia cashmere goat populations using whole-genome genotyping

OBJECTIVE

As a charismatic species, cashmere goats have rich genetic resources. In the Inner Mongolia Autonomous Region, there are three cashmere goat varieties named and approved by the state. These goats are renowned for their high cashmere production and superior cashmere quality. Therefore, it is vitally important to protect their genetic resources as they will serve as breeding material for developing new varieties in the future.

METHODS

Three breeds including Inner Mongolia cashmere goats (IMCG), Hanshan White cashmere goats (HS), and Ujimqin white cashmere goats (WZMQ) were studied. IMCG were of three types: Aerbas (AEBS), Erlangshan (ELS), and Alashan (ALS). Nine DNA samples were collected for each population, and they were genomically re-sequenced to obtain high-depth data. The genetic diversity parameters of each population were estimated to determine selection intensity. Principal component analysis, phylogenetic tree construction and genetic differentiation parameter estimation were performed to determine genetic relationships among populations.

RESULTS

Samples from the 45 individuals from the five goat populations were sequenced, and 30,601,671 raw single nucleotide polymorphisms (SNPs) obtained. Then, variant calling was conducted using the reference genome, and 17,214,526 SNPs were retained after quality control. Individual sequencing depth of individuals ranged from 21.13× to 46.18×, with an average of 28.5×. In the AEBS, locus polymorphism (79.28) and expected heterozygosity (0.2554) proportions were the lowest, and the homologous consistency ratio (0.1021) and average inbreeding coefficient (0.1348) were the highest, indicating that this population had strong selection intensity. Conversely, ALS and WZMQ selection intensity was relatively low. Genetic distance between HS and the other four populations was relatively high, and genetic exchange existed among the other four populations.

CONCLUSION

The Inner Mongolia cashmere goat (AEBS type) population has a relatively high selection intensity and a low genetic diversity. The IMCG (ALS type) and WZMQ populations had relatively low selection intensity and high genetic diversity. The genetic distance between HS and the other four populations was relatively high, with a moderate degree of differentiation. Overall, these genetic variations provide a solid foundation for resource identification of Inner Mongolia Autonomous Region cashmere goats in the future.

Anthropogenic events and responses to environmental stress are shaping the genomes of Ethiopian indigenous goats

Anthropological and biophysical processes have shaped livestock genomes over Millenia and can explain their current geographic distribution and genetic divergence. We analyzed 57 Ethiopian indigenous domestic goat genomes alongside 67 equivalents of east, west, and north-west African, European, South Asian, Middle East, and wild Bezoar goats. Cluster, ADMIXTURE (K = 4) and phylogenetic analysis revealed four genetic groups comprising African, European, South Asian, and wild Bezoar goats. The Middle Eastern goats had an admixed genome of these four genetic groups. At K = 5, the West African Dwarf and Moroccan goats were separated from East African goats demonstrating a likely historical legacy of goat arrival and dispersal into Africa via the coastal Mediterranean Sea and the Horn of Africa. FST, XP-EHH, and Hp analysis revealed signatures of selection in Ethiopian goats overlaying genes for thermo-sensitivity, oxidative stress response, high-altitude hypoxic adaptation, reproductive fitness, pathogen defence, immunity, pigmentation, DNA repair, modulation of renal function and integrated fluid and electrolyte homeostasis. Notable examples include TRPV1 (a nociception gene); PTPMT1 (a critical hypoxia survival gene); RETREG (a regulator of reticulophagy during starvation), and WNK4 (a molecular switch for osmoregulation). These results suggest that human-mediated translocations and adaptation to contrasting environments are shaping indigenous African goat genomes.

Structural variant landscapes reveal convergent signatures of evolution in sheep and goats

BACKGROUND

Sheep and goats have undergone domestication and improvement to produce similar phenotypes, which have been greatly impacted by structural variants (SVs). Here, we report a high-quality chromosome-level reference genome of Asiatic mouflon, and implement a comprehensive analysis of SVs in 897 genomes of worldwide wild and domestic populations of sheep and goats to reveal genetic signatures underlying convergent evolution.

RESULTS

We characterize the SV landscapes in terms of genetic diversity, chromosomal distribution and their links with genes, QTLs and transposable elements, and examine their impacts on regulatory elements. We identify several novel SVs and annotate corresponding genes (e.g., BMPR1B, BMPR2, RALYL, COL21A1, and LRP1B) associated with important production traits such as fertility, meat and milk production, and wool/hair fineness. We detect signatures of selection involving the parallel evolution of orthologous SV-associated genes during domestication, local environmental adaptation, and improvement. In particular, we find that fecundity traits experienced convergent selection targeting the gene BMPR1B, with the DEL00067921 deletion explaining ~10.4% of the phenotypic variation observed in goats.

CONCLUSIONS

Our results provide new insights into the convergent evolution of SVs and serve as a rich resource for the future improvement of sheep, goats, and related livestock.

A Review on Indigenous Goats of East Africa: A Case for Conservation and Management

Indigenous goats are important in the livelihoods of rural households in East African countries. This is due to their ability to produce and reproduce in different environments and climatic conditions. Even though these indigenous goats are important, there is little available information on the genetic characterization of these breeds in Africa and at the international level. This paper reviews the status of indigenous goats, highlighting their production systems, phenotypic and genetic characteristics, and genetic diversity, and proposes potential ways for sustainable improvement and conservation in East African countries. Most households use traditional production systems with various uncharacterized goat breeds and ecotypes, which are hence named after the tribe or locality in which they are found. Most of these goats are classified as small East African breeds, with significant variability in morphological features. Some of the challenges to goat production in this region are indiscriminate crossbreeding, lack of pedigree records, parasites and disease incidences, low-quality pastures, and low levels of management. There is a need for a collaborative approach amongst the actors in goat breeding value chains as well as integrating modern genomic tools into breeding programs to enhance selection. This will ensure the resilience and sustainability of these unique indigenous goat populations in East Africa.

Genetic diversity, population structure and kinship relationships highlight the environmental influence on Uganda's indigenous goat populations

Knowledge about genetic diversity and population structure among goat populations is essential for understanding environmental adaptation and fostering efficient utilization, development, and conservation of goat breeds. Uganda's indigenous goats exist in three phenotypic groups: Mubende, Kigezi, and Small East African. However, a limited understanding of their genetic attributes and population structure hinders the development and sustainable utilization of the goats. Using the Goat Illumina 60k chip International Goat Genome Consortium V2, the whole-genome data for 1,021 indigenous goats sourced from 10 agroecological zones in Uganda were analyzed for genetic diversity and population structure. A total of 49,337 (82.6%) single-nucleotide polymorphism markers were aligned to the ARS-1 goat genome and used to assess the genetic diversity, population structure, and kinship relationships of Uganda's indigenous goats. Moderate genetic diversity was observed. The observed and expected heterozygosities were 0.378 and 0.383, the average genetic distance was 0.390, and the average minor allele frequency was 0.30. The average inbreeding coefficient (Fis) was 0.014, and the average fixation index (Fst) was 0.016. Principal component analysis, admixture analysis, and discriminant analysis of principal components grouped the 1,021 goat genotypes into three genetically distinct populations that did not conform to the known phenotypic populations but varied across environmental conditions. Population 1, comprising Mubende (90%) and Kigezi (8.1%) goats, is located in southwest and central Uganda, a warm and humid environment. Population 2, which is 59% Mubende and 49% Small East African goats, is located along the Nile Delta in northwestern Uganda and around the Albertine region, a hot and humid savannah grassland. Population 3, comprising 78.4% Small East African and 21.1% Mubende goats, is found in northeastern to eastern Uganda, a hot and dry Commiphora woodlands. Genetic diversity and population structure information from this study will be a basis for future development, conservation, and sustainable utilization of Uganda's goat genetic resources.

Genomic analysis uncovers novel candidate genes related to adaptation to tropical climates and milk production traits in native goats

BACKGROUND

Since domestication, both evolutionary forces and human selection have played crucial roles in producing adaptive and economic traits, resulting in animal breeds that have been selected for specific climates and different breeding goals. Pakistani goat breeds have acquired genomic adaptations to their native climate conditions, such as tropical and hot climates. In this study, using next-generation sequencing data, we aimed to assess the signatures of positive selection in three native Pakistani goats, known as milk production breeds, that have been well adapted to their local climate.

RESULTS

To explore the genomic relationship between studied goat populations and their population structure, whole genome sequence data from native goat populations in Pakistan (n = 26) was merged with available worldwide goat genomic data (n = 184), resulting in a total dataset of 210 individuals. The results showed a high genetic correlation between Pakistani goats and samples from North-East Asia. Across all populations analyzed, a higher linkage disequilibrium (LD) level (- 0.59) was found in the Pakistani goat group at a genomic distance of 1 Kb. Our findings from admixture analysis (K = 5 and K = 6) showed no evidence of shared genomic ancestry between Pakistani goats and other goat populations from Asia. The results from genomic selection analysis revealed several candidate genes related to adaptation to tropical/hot climates (such as; KITLG, HSPB9, HSP70, HSPA12B, and HSPA12B) and milk production related-traits (such as IGFBP3, LPL, LEPR, TSHR, and ACACA) in Pakistani native goat breeds.

CONCLUSIONS

The results from this study shed light on the structural variation in the DNA of the three native Pakistani goat breeds. Several candidate genes were discovered for adaptation to tropical/hot climates, immune responses, and milk production traits. The identified genes could be exploited in goat breeding programs to select efficient breeds for tropical/hot climate regions.

Genomic Inbreeding and Runs of Homozygosity Analysis of Cashmere Goat

Cashmere goats are valuable genetic resources which are famous worldwide for their high-quality fiber. Runs of homozygosity (ROHs) have been identified as an efficient tool to assess inbreeding level and identify related genes under selection. However, there is limited research on ROHs in cashmere goats. Therefore, we investigated the ROH pattern, assessed genomic inbreeding levels and examined the candidate genes associated with the cashmere trait using whole-genome resequencing data from 123 goats. Herein, the Inner Mongolia cashmere goat presented the lowest inbreeding coefficient of 0.0263. In total, we identified 57,224 ROHs. Seventy-four ROH islands containing 50 genes were detected. Certain identified genes were related to meat, fiber and milk production (FGF1, PTPRM, RERE, GRID2, RARA); fertility (BIRC6, ECE2, CDH23, PAK1); disease or cold resistance and adaptability (PDCD1LG2, SVIL, PRDM16, RFX4, SH3BP2); and body size and growth (TMEM63C, SYN3, SDC1, STRBP, SMG6). 135 consensus ROHs were identified, and we found candidate genes (FGF5, DVL3, NRAS, KIT) were associated with fiber length or color. These findings enhance our comprehension of inbreeding levels in cashmere goats and the genetic foundations of traits influenced by selective breeding. This research contributes significantly to the future breeding, reservation and use of cashmere goats and other goat breeds.

Runs of Homozygosity Detection and Selection Signature Analysis for Local Goat Breeds in Yunnan, China

Runs of Homozygosity (ROH) are continuous homozygous DNA segments in diploid genomes, which have been used to estimate the genetic diversity, inbreeding levels, and genes associated with specific traits in livestock. In this study, we analyzed the resequencing data from 10 local goat breeds in Yunnan province of China and five additional goat populations obtained from a public database. The ROH analysis revealed 21,029 ROH segments across the 15 populations, with an average length of 1.27 Mb, a pattern of ROH, and the assessment of the inbreeding coefficient indicating genetic diversity and varying levels of inbreeding. iHS (integrated haplotype score) was used to analyze high-frequency Single-Nucleotide Polymorphisms (SNPs) in ROH regions, specific genes related to economic traits such as coat color and weight variation. These candidate genes include OCA2 (OCA2 melanosomal transmembrane protein) and MLPH (melanophilin) associated with coat color, EPHA6 (EPH receptor A6) involved in litter size, CDKAL1 (CDK5 regulatory subunit associated protein 1 like 1) and POMC (proopiomelanocortin) linked to weight variation and some putative genes associated with high-altitude adaptability and immune. This study uncovers genetic diversity and inbreeding levels within local goat breeds in Yunnan province, China. The identification of specific genes associated with economic traits and adaptability provides actionable insights for utilization and conservation efforts.

Whole-genome SNP genotyping unveils ancestral and recent introgression in wild and domestic goats

After the domestication of goats around 10,000 years before the present (BP), humans transported goats far beyond the range of their wild ancestor, the bezoar goat. This brought domestic goats into contact with many wild goat species such as ibex and markhor, enabling introgression between domestic and wild goats. To investigate this, while shedding light on the taxonomic status of wild and domestic goats, we analysed genome-wide SNP data of 613 specimens from 14 taxonomic units, including Capra hircus, C. pyrenaica, C. ibex (from Switzerland, Austria, Germany and Slovenia), C. aegagrus aegagrus, C. a. cretica, C. h. dorcas, C. caucasica caucasica, C. c. severtzovi, C. c. cylindricornis, C. falconeri, C. sibirica sibirica, C. s. alaiana and C. nubiana, as well as Oreamnos americanus (mountain goat) as an outgroup. To trace gene flow between domestic and wild goats, we integrated genotype data of local goat breeds from the Alps as well as from countries such as Spain, Greece, Türkiye, Egypt, Sudan, Iran, Russia (Caucasus and Altai) and Pakistan. Our phylogenetic analyses displayed a clear separation between bezoar-type and ibex-type clades with wild goats from the Greek islands of Crete and Youra clustered within domestic goats, confirming their feral origin. Our analyses also revealed gene flow between the lineages of Caucasian tur and domestic goats that most likely occurred before or during early domestication. Within the clade of domestic goats, analyses inferred gene flow between African and Iberian goats. The detected events of introgression were consistent with previous reports and offered interesting insights into the historical relationships among domestic and wild goats.

Polymorphism of the MTNR1A Melatonin Receptor Gene in Goat Breeds of Northern Italy

Melatonin receptor MT1, encoded by the MTNR1A gene, is the main one involved in the seasonal regulation of reproductive activity. A correlation between this gene polymorphism and reproductive performance has been demonstrated in sheep. To date, no data about MTNR1A gene polymorphism are available regarding Italian goat breeds other than the Sarda goat. This study aimed to detect any PCR-RFLP polymorphic sites of MTNR1A using MnlI and RsaI enzymes in Northern Italian goat breeds, which are characterized by a pronounced reproductive seasonality. One-hundred-eight adult female goats belonging to four different breeds were included in the study (i.e., Frisa Valtellinese, n = 29; Orobica, n = 23; Lariana, n = 29; Camosciata delle Alpi, n = 27). Blood was sampled from each goat. Genomic DNA was extracted from each sample and the main part of exon II of MTNR1A gene was amplified by PCR and digested with MnlI and RsaI enzymes. Unexpectedly, none of the fragments were found to be polymorphic. The absence of polymorphism may be linked to the macro group of goat breeds that evolved during human migrations. Breeds of the Alpine-European strain would appear to show no polymorphism, as confirmed by our study, whereas breeds belonging to the Mediterranean-African or Asian-Middle Eastern strains do.

The genomic landscape of mammal domestication might be orchestrated by selected transcription factors regulating brain and craniofacial development

Domestication transforms once wild animals into tamed animals that can be then exploited by humans. The process entails modifications in the body, cognition, and behavior that are essentially driven by differences in gene expression patterns. Although genetic and epigenetic mechanisms were shown to underlie such differences, less is known about the role exerted by trans-regulatory molecules, notably transcription factors (TFs) in domestication. In this paper, we conducted extensive in silico analyses aimed to clarify the TF landscape of mammal domestication. We first searched the literature, so as to establish a large list of genes selected with domestication in mammals. From this list, we selected genes experimentally demonstrated to exhibit TF functions. We also considered TFs displaying a statistically significant number of targets among the entire list of (domestication) selected genes. This workflow allowed us to identify 5 candidate TFs (SOX2, KLF4, MITF, NR3C1, NR3C2) that were further assessed in terms of biochemical and functional properties. We found that such TFs-of-interest related to mammal domestication are all significantly involved in the development of the brain and the craniofacial region, as well as the immune response and lipid metabolism. A ranking strategy, essentially based on a survey of protein-protein interactions datasets, allowed us to identify SOX2 as the main candidate TF involved in domestication-associated evolutionary changes. These findings should help to clarify the molecular mechanics of domestication and are of interest for future studies aimed to understand the behavioral and cognitive changes associated to domestication.

Whole-genome resequencing of Dorper and Hu sheep to reveal selection signatures associated with important traits

Dorper and Hu sheep exhibit different characteristics in terms of reproduction, growth, and meat quality. Comparison of the genomes of two breeds help to reveal important genomic information. In this study, whole genome resequencing of 30 individuals (Dorper, DB and Hu sheep, HY) identified 15,108,125 single nucleotide polymorphisms (SNPs). Population differentiation (Fst) and cross population extended haplotype homozygosity (XP-EHH) were performed for selective signal analysis. In total, 106 and 515 overlapped genes were present in both the Fst results and XP-EHH results in HY vs DB and in DB vs HY, respectively. In HY vs DB, 106 genes were enriched in 12 GO terms and 83 KEGG pathways, such as ATP binding (GO:0005524) and PI3K-Akt signaling pathway (oas04151). In DB vs HY, 515 genes were enriched in 109 GO terms and 215 KEGG pathways, such as skeletal muscle cell differentiation (GO:0035914) and MAPK signaling pathway (oas04010). According to the annotation results, we identified a series of candidate genes associated with reproduction (UNC5C, BMPR1B, and GLIS1), meat quality (MECOM, MEF2C, and MYF6), and immunity (GMDS, GALK1, and ITGB4). Our investigation has uncovered genomic information for important traits in sheep and provided a basis for subsequent studies of related traits.

Genetic diversity and historical demography of underutilised goat breeds in North-Western Europe

In the last decade, several studies aimed at dissecting the genetic architecture of local small ruminant breeds to discover which variations are involved in the process of adaptation to environmental conditions, a topic that has acquired priority due to climate change. Considering that traditional breeds are a reservoir of such important genetic variation, improving the current knowledge about their genetic diversity and origin is the first step forward in designing sound conservation guidelines. The genetic composition of North-Western European archetypical goat breeds is still poorly exploited. In this study we aimed to fill this gap investigating goat breeds across Ireland and Scandinavia, including also some other potential continental sources of introgression. The PCA and Admixture analyses suggest a well-defined cluster that includes Norwegian and Swedish breeds, while the crossbred Danish landrace is far apart, and there appears to be a close relationship between the Irish and Saanen goats. In addition, both graph representation of historical relationships among populations and f4-ratio statistics suggest a certain degree of gene flow between the Norse and Atlantic landraces. Furthermore, we identify signs of ancient admixture events of Scandinavian origin in the Irish and in the Icelandic goats. The time when these migrations, and consequently the introgression, of Scandinavian-like alleles occurred, can be traced back to the Viking colonisation of these two isles during the Viking Age (793-1066 CE). The demographic analysis indicates a complicated history of these traditional breeds with signatures of bottleneck, inbreeding and crossbreeding with the improved breeds. Despite these recent demographic changes and the historical genetic background shaped by centuries of human-mediated gene flow, most of them maintained their genetic identity, becoming an irreplaceable genetic resource as well as a cultural heritage.

Phylogenomics Reveals High Levels of Incomplete Lineage Sorting at the Ancestral Nodes of the Macaque Radiation

The genus Macaca includes 23 species assigned into 4 to 7 groups. It exhibits the largest geographic range and represents the most successful example of adaptive radiation of nonhuman primates. However, intrageneric phylogenetic relationships among species remain controversial and have not been resolved so far. In this study, we conducted a phylogenomic analysis on 16 newly generated and 8 published macaque genomes. We found strong evidence supporting the division of this genus into 7 species groups. Incomplete lineage sorting (ILS) was the primary factor contributing to the discordance observed among gene trees; however, we also found evidence of hybridization events, specifically between the ancestral arctoides/sinica and silenus/nigra lineages that resulted in the hybrid formation of the fascicularis/mulatta group. Combined with fossil data, our phylogenomic data were used to establish a scenario for macaque radiation. These findings provide insights into ILS and potential ancient introgression events that were involved in the radiation of macaques, which will lead to a better understanding of the rapid speciation occurring in nonhuman primates.

Genome-Wide Association and Pathway Analysis of Carcass and Meat Quality Traits in Karachai Young Goats

Goats with diverse economic phenotypic traits play an important role in animal husbandry. However, the genetic mechanisms underlying complex phenotypic traits are unclear in goats. Genomic studies of variations provided a lens to identify functional genes. The work aimed to search for candidate genes related to body measurements and body weight of Karachai goats and develop an experimental PCR-RV test system for genotyping significant SNPs. Comparison of GWAS results for ages 4 and 8 months revealed 58 common SNPs for significant genotypes. 11 common SNPs were identified for body weight, 4 SNPs-for group of traits withers height, rump height, body length, 2 SNPs-for withers height and rump height, 1 SNP-for body length and chest depth. Structural annotation of genomic regions covering a window of ±0.20 Mb showed the presence of 288 genes; 52 of them had the described functions in accordance with gene ontology. The main molecular functions of proteins encoded by these genes are the regulation of transcription, cell proliferation, angiogenesis, body growth, fatty acid and lipid metabolism, nervous system development, and spermatogenesis. SNPs common to body weight and localized within a window of ±200 kb from the structural genes CRADD, HMGA2, MSRB3, FUT8, MAX, and RAB15 were selected to create a test system. The study of meat productivity after slaughter and chemical analysis of muscle tissue in Karachai goats at the age of 8 months of different genotypes according to the identified SNPs revealed that rs268269710 is the most promising for further research and use in breeding. The GG genotype is associated with a larger live weight of animals, a larger carcass yield, the content of the boneless part in it, and the ratio of protein and adipose tissue in meat preferred for dietary nutrition. These results will contribute to the genetic improvement of Karachai goats.

Mitochondrial DNA analyses revealed distinct lineages in an alpine mammal, Siberian ibex (Capra sibirica) in Xinjiang, China

Maternal lineages of mitochondrial DNA (mtDNA) are recognized as important components of intra and interspecific biodiversity and help us to disclose the phylogeny and divergence times of many taxa. Species of the genus Capra are canonical mountain dwellers. Among these is the Siberian ibex (Capra sibirica), which is regarded as a relic species whose intraspecific classification has been controversial so far. We collected 58 samples in Xinjiang, China, and analyzed the mtDNA genes to shed light on the intraspecific relationships of the C. sibirica populations and estimate the divergence time. Intriguingly, we found that the mtDNA sequences of C. sibirica split into two main lineages in both phylogenetic and network analyses: the Southern lineage, sister to Capra falconeri, consisting of samples from Ulugqat, Kagilik (both in Xinjiang), India, and Tajikistan; and the Northern lineage further divided into four monophyletic clades A-D corresponding to their geographic origins. Samples from Urumqi, Sawan, and Arturk formed a distinct monophyletic clade C within the Northern lineage. The genetic distance between the C. sibirica clades ranges from 3.0 to 8.6%, with values of F ST between 0.839 and 0.960, indicating notable genetic differentiation. The split of the genus Capra occurred approximately 6.75 Mya during the late Miocene. The Northern lineage diverged around 5.88 Mya, followed by the divergence of Clades A-D from 3.30 to 1.92 Mya during the late Pliocene and early Pleistocene. The radiation between the Southern lineage and C. falconeri occurred at 2.29 Mya during the early Pleistocene. Our results highlight the importance of extensive sampling when relating to genetic studies of alpine mammals and call for further genomic studies to draw definitive conclusions.

A missense mutation in RRM1 contributes to animal tameness

The increased tameness to reduce avoidance of human in wild animals has been long proposed as the key step of animal domestication. The tameness is a complex behavior trait and largely determined by genetic factors. However, the underlying genetic mutations remain vague and how they influence the animal behaviors is yet to be explored. Behavior tests of a wild-domestic hybrid goat population indicate the locus under strongest artificial selection during domestication may exert a huge effect on the flight distance. Within this locus, only one missense mutation RRM1I241V which was present in the early domestic goat ~6500 years ago. Genome editing of RRM1I241V in mice showed increased tameness and sociability and reduced anxiety. These behavioral changes induced by RRM1I241V were modulated by the alternation of activity of glutamatergic synapse and some other synapse-related pathways. This study established a link between RRM1I241V and tameness, demonstrating that the complex behavioral change can be achieved by mutations under strong selection during animal domestication.

Convergent molecular evolution of thermogenesis and circadian rhythm in Arctic ruminants

The muskox and reindeer are the only ruminants that have evolved to survive in harsh Arctic environments. However, the genetic basis of this Arctic adaptation remains largely unclear. Here, we compared a de novo assembled muskox genome with reindeer and other ruminant genomes to identify convergent amino acid substitutions, rapidly evolving genes and positively selected genes among the two Arctic ruminants. We found these candidate genes were mainly involved in brown adipose tissue (BAT) thermogenesis and circadian rhythm. Furthermore, by integrating transcriptomic data from goat adipose tissues (white and brown), we demonstrated that muskox and reindeer may have evolved modulating mitochondrion, lipid metabolism and angiogenesis pathways to enhance BAT thermogenesis. In addition, results from co-immunoprecipitation experiments prove that convergent amino acid substitution of the angiogenesis-related gene hypoxia-inducible factor 2alpha (HIF2A), resulting in weakening of its interaction with prolyl hydroxylase domain-containing protein 2 (PHD2), may increase angiogenesis of BAT. Altogether, our work provides new insights into the molecular mechanisms involved in Arctic adaptation.

Demographic history and genomic consequences of 10,000 generations of isolation in a wild mammal

Increased human activities caused the isolation of populations in many species-often associated with genetic depletion and negative fitness effects. The effects of isolation are predicted by theory, but long-term data from natural populations are scarce. We show, with full genome sequences, that common voles (Microtus arvalis) in the Orkney archipelago have remained genetically isolated from conspecifics in continental Europe since their introduction by humans over 5,000 years ago. Modern Orkney vole populations are genetically highly differentiated from continental conspecifics as a result of genetic drift processes. Colonization likely started on the biggest Orkney island and vole populations on smaller islands were gradually split off, without signs of secondary admixture. Despite having large modern population sizes, Orkney voles are genetically depauperate and successive introductions to smaller islands resulted in further reduction of genetic diversity. We detected high levels of fixation of predicted deleterious variation compared with continental populations, particularly on smaller islands, yet the fitness effects realized in nature are unknown. Simulations showed that predominantly mildly deleterious mutations were fixed in populations, while highly deleterious mutations were purged early in the history of the Orkney population. Relaxation of selection overall due to benign environmental conditions on the islands and the effects of soft selection may have contributed to the repeated, successful establishment of Orkney voles despite potential fitness loss. Furthermore, the specific life history of these small mammals, resulting in relatively large population sizes, has probably been important for their long-term persistence in full isolation.

Whole genome sequencing of simmental cattle for SNP and CNV discovery

BACKGROUD

The single nucleotide polymorphisms (SNPs) and copy number variations (CNVs) are two major genomic variants, which play crucial roles in evolutionary and phenotypic diversity.

RESULTS

In this study, we performed a comprehensive analysis to explore the genetic variations (SNPs and CNVs) of high sperm motility (HSM) and poor sperm motility (PSM) Simmental bulls using the high-coverage (25×) short-read next generation sequencing and single-molecule long reads sequencing data. A total of ~ 15 million SNPs and 2,944 CNV regions (CNVRs) were detected in Simmental bulls, and a set of positive selected genes (PSGs) and CNVRs were found to be overlapped with quantitative trait loci (QTLs) involving immunity, muscle development, reproduction, etc. In addition, we detected two new variants in LEPR, which may be related to the artificial breeding to improve important economic traits. Moreover, a set of genes and pathways functionally related to male fertility were identified. Remarkably, a CNV on SPAG16 (chr2:101,427,468 - 101,429,883) was completely deleted in all poor sperm motility (PSM) bulls and half of the bulls in high sperm motility (HSM), which may play a crucial role in the bull-fertility.

CONCLUSIONS

In conclusion, this study provides a valuable genetic variation resource for the cattle breeding and selection programs.

Analysis of genomic copy number variations through whole-genome scan in Chinese Qaidam cattle

Qaidam cattle (CDM) are indigenous breed inhabiting Northwest China. In the present study, we newly sequenced 20 Qaidam cattle to investigate the copy number variants (CNVs) based on the ARS-UMD1.2 reference genome. We generated the CNV region (CNVR) datasets to explore the genomic CNV diversity and population stratification. The other four cattle breeds (Xizang cattle, XZ; Kazakh cattle, HSK; Mongolian cattle, MG; and Yanbian cattle, YB) from the regions of North China embracing 43 genomic sequences were collected and are distinguished from each of the other diverse populations by deletions and duplications. We also observed that the number of duplications was significantly more than deletions in the genome, which may be less harmful to gene formation and function. At the same time, only 1.15% of CNVRs overlapped with the exon region. Population differential CNVRs and functional annotations between the Qaidam cattle population and other cattle breeds revealed the functional genes related to immunity (MUC6), growth (ADAMTSL3), and adaptability (EBF2). Our analysis has provided numerous genomic characteristics of some Chinese cattle breeds, which are valuable as customized biological molecular markers in cattle breeding and production.

Resequencing of a Pekin duck breeding population provides insights into the genomic response to short-term artificial selection

BACKGROUND

Short-term, intense artificial selection drives fast phenotypic changes in domestic animals and leaves imprints on their genomes. However, the genetic basis of this selection response is poorly understood. To better address this, we employed the Pekin duck Z2 pure line, in which the breast muscle weight was increased nearly 3-fold after 10 generations of breeding. We denovo assembled a high-quality reference genome of a female Pekin duck of this line (GCA_003850225.1) and identified 8.60 million genetic variants in 119 individuals among 10 generations of the breeding population.

RESULTS

We identified 53 selected regions between the first and tenth generations, and 93.8% of the identified variations were enriched in regulatory and noncoding regions. Integrating the selection signatures and genome-wide association approach, we found that 2 regions covering 0.36 Mb containing UTP25 and FBRSL1 were most likely to contribute to breast muscle weight improvement. The major allele frequencies of these 2 loci increased gradually with each generation following the same trend. Additionally, we found that a copy number variation region containing the entire EXOC4 gene could explain 1.9% of the variance in breast muscle weight, indicating that the nervous system may play a role in economic trait improvement.

CONCLUSIONS

Our study not only provides insights into genomic dynamics under intense artificial selection but also provides resources for genomics-enabled improvements in duck breeding.