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Background The dazzling phenotypic characteristics of male Indian peafowl (Pavo cristatus) are attractive both to the female of the species and to humans. However, little is known about the evolution of the phenotype and phylogeny of these birds at the whole-genome level. So far, there are no reports regarding the genetic mechanism of the formation of leucism plumage in this variant of Indian peafowl. Results A draft genome of Indian peafowl was assembled, with a genome size of 1.05 Gb (the sequencing depth is 362×), and contig and scaffold N50 were up to 6.2 and 11.4 Mb, respectively. Compared with other birds, Indian peafowl showed changes in terms of metabolism, immunity, and skeletal and feather development, which provided a novel insight into the phenotypic evolution of peafowl, such as the large body size and feather morphologies. Moreover, we determined that the phylogeny of Indian peafowl was more closely linked to turkey than chicken. Specifically, we first identified that PMEL was a potential causal gene leading to the formation of the leucism plumage variant in Indian peafowl. Conclusions This study provides an Indian peafowl genome of high quality, as well as a novel understanding of phenotypic evolution and phylogeny of Indian peafowl. These results provide a valuable reference for the study of avian genome evolution. Furthermore, the discovery of the genetic mechanism for the development of leucism plumage is both a breakthrough in the exploration of peafowl plumage and also offers clues and directions for further investigations of the avian plumage coloration and artificial breeding in peafowl.

The limited knowledge of genomic noncoding and regulatory regions has restricted our ability to decipher the genetic mechanisms underlying complex traits in pigs. In this study, we characterized the spatiotemporal landscape of putative enhancers and promoters and their target genes by combining H3K27ac-targeted ChIP-Seq and RNA-Seq in fetal (prenatal days 74-75) and adult (postnatal days 132-150) tissues (brain, liver, heart, muscle and small intestine) sampled from Asian aboriginal Bama Xiang and European highly selected Large White pigs of both sexes. We identified 101,290 H3K27ac peaks, marking 18,521 promoters and 82,769 enhancers, including peaks that were active across all tissues and developmental stages (which could indicate safe harbor locus for exogenous gene insertion) and tissue- and developmental stage-specific peaks (which regulate gene pathways matching tissue- and developmental stage-specific physiological functions). We found that H3K27ac and DNA methylation in the promoter region of the XIST gene may be involved in X chromosome inactivation and demonstrated the utility of the present resource for revealing the regulatory patterns of known causal genes and prioritizing candidate causal variants for complex traits in pigs. In addition, we identified an average of 1,124 super-enhancers per sample and found that they were more likely to show tissue-specific activity than ordinary peaks. We have developed a web browser to improve the accessibility of the results ( http://segtp.jxau.edu.cn/pencode/?genome=susScr11 ).

To determine the genetic basis of pork eating quality traits and cooking loss, we herein performed a genome-wide association study (GWAS) for tenderness, juiciness, oiliness, umami, overall liking and cooking loss by using whole genome sequences of heterogeneous stock F6 pigs which were generated by crossing 4 typical western pig breeds (Duroc, Landrace, Large White and Pietrain) and 4 typical Asian pig breeds (Erhualian, Laiwu, Bamaxiang and Tibetan). We identified 50 associated loci (QTLs) and most of them are novel. Seven loci also showed pleiotropic associations with different traits. In addition, we identified multiple promising candidate genes for these traits, including PAK1 and AQP11 for cooking loss, EP300 for tenderness, SDK1 for juiciness, FITM2 and 5-linked MYH genes for oiliness, and TNNI2 and TNNT3 for overall liking. Our results provide not only a better understanding of the genetic basis for meat quality, but also a potential application in future breeding for these complex traits.

Collichthys lucidus (C. lucidus) is a commercially important marine fish species distributed in coastal regions of East Asia with the X1X1X2X2/X1X2Y multiple sex chromosome system. The karyotype for female C. lucidus is 2n = 48, while 2n = 47 for male ones. Therefore, C. lucidus is also an excellent model to investigate teleost sex-determination and sex chromosome evolution. We reported the first chromosome genome assembly of C. lucidus using Illumina short-read, PacBio long-read sequencing and Hi-C technology. An 877 Mb genome was obtained with a contig and scaffold N50 of 1.1 Mb and 35.9 Mb, respectively. More than 97% BUSCOs genes were identified in the C. lucidus genome and 28,602 genes were annotated. We identified potential sex-determination genes along chromosomes and found that the chromosome 1 might be involved in the formation of Y specific metacentric chromosome. The first C. lucidus chromosome-level reference genome lays a solid foundation for the following population genetics study, functional gene mapping of important economic traits, sex-determination and sex chromosome evolution studies for Sciaenidae and teleosts., Design Type(s)sequence assembly objective • sequence annotation objective • transcription profiling designMeasurement Type(s)whole genome sequencing assay • transcript expression assayTechnology Type(s)DNA sequencing • RNA sequencingFactor Type(s)organism partSample Characteristic(s)Collichthys lucidus Machine-accessible metadata file describing the reported data (ISA-Tab format)

DNA methylation is an essential epigenetic modification that significantly regulates gene expression during development and differentiation. In this study, genome-wide methylation analysis of different gonads of the large yellow croaker was performed using whole-genome bisulfite sequencing (WGBS), which has characterized DNA methylation patterns in gonad tissue and identified candidate regions for future studies. Clustering analysis revealed that male and neomale methylation patterns were close compared to female. Based on KEGG pathway analysis of differentially methylated genes, we obtained signaling pathways related to gonadal development. We further investigated the methylation status of previously reported sex determination genes, and found that these genes showed different methylation status in three types of gonads, which may provide important clues to reveal the sex determination genes in the large yellow croaker. Furthermore, combined with transcriptome analysis, we found 7 sex-related genes in three comparison groups where expression negatively correlated with methylation.

A high-density genetic linkage map is essential for the studies of comparative genomics and gene mapping, and can facilitate assembly of reference genome. Herein, we constructed a high-density genetic linkage map with 8,094 SNPs selected from 113 sequenced fish of a F1 family. Ultimately, the consensus map spanned 3818.24 cM and covered nearly the whole genome (99.4%) with a resolution of 0.47 cM. 1,457 scaffolds spanning 435.15 Mb were anchored onto 24 linkage groups, accounting for 80.7% of the draft genome assembly of the yellow drum. Comparative genomic analyses with medaka and zebrafish genomes showed superb chromosome-scale synteny between yellow drum and medaka. QTL mapping and association analysis congruously revealed 22 QTLs for growth-related traits and 13 QTLs for sex dimorphism. Some important candidate genes such as PLA2G4A, BRINP3 and P2RY1 were identified from these growth-related QTL regions. A gene family including DMRT1, DMRT2 and DMRT3 was identified from these sex-related QTL regions on the linkage group LG9. We demonstrate that this linkage map can facilitate the ongoing marker-assisted selection and genomic and genetic studies for yellow drum.

Yellow drum (Nibea albiflora) is a commercially important marine fish, which is widely distributed in the coastal waters of China, Japan and Korea. Wild yellow drum resources have dramatically declined due to overfishing and ocean pollution. Genetic data can contribute to biodiversity conservation and protection. And molecular markers can play important roles in genetic breeding and aid in germplasm preservation in fish. In this study, 11 tissues (brain, heart, liver, kidney, muscle, head kidney, skin, fin, spleen, gonad and air bladder) were collected for pooled RNA sequencing. The unigenes were assembled using Trinity and EvidentialGene, and were then aligned to nr, nt, Swiss-Prot GO, KEGG, and KOG for annotation. Molecular markers (e.g. simple sequence repeat, SSR and single nucleotide polymorphism, SNP) were detected using MIcroSAtellite identification tool (MISA) and Genome Analysis Tool Kit (GATK). All clean reads were assembled into 109,209 transcripts, and 31,183 unigenes were generated after pruning and classifying, ranging from 201 to 19,857 bp in length (1230 bp in average), and 26,728 (85.7%) assembled unigenes had significant hits in public databases. Total of 27 and 103 unigenes were respectively identified as involved in growth- and immune-related pathways in the N. albiflora transcriptome. In addition, we identified a considerable quantity of molecular markers, including 11,484 SSRs and 56,186 SNPs. The growth- and immune-relevant genes and the molecular markers identified here provided a meaningful reference gene set and laid a foundation for future genetic selection and breeding for this species.

Follicle-stimulating hormone (FSH) is a pituitary gonadotropin regulating reproduction in mammals. Overexpression of the exogenous FSHα/β genes from Chinese Erhualian pigs improved female fecundity of transgenic (TG) mice and male spermatogenesis ability of Large White TG boars. Here, we investigated the impact of the exogenous FSHα/β genes on female reproductive performance of Large White TG pigs. First, we identified the integration site of the exogenous FSHα/β genes at 140,646,456 bp on chromosome 9 in these TG pigs using whole-genome sequencing. Then, we showed that TG gilts had higher levels of serum FSH and FSHβ protein in pituitary while had a potentially lower number of born piglets than their wild-type half sibs. TG gilts grew healthily and normally without significant difference in growth and health parameters as compared to WT gilts. The expression levels of FSHR, LHR, ESR1 and ESR2 were significantly lower in TG gilts than in WT gilts at the age of 300 days. Taken together, we proposed that the overexpressed FSHα/β transgenes could cause deteriorate fecundity via disturbing the normal expression of the endogenous reproduction-related genes in female pigs. Our findings provide insight into the effect of overexpression of FSHα/β on female reproduction performance in pigs.

Serum glucose and lipid levels are associated with diabetes mellitus and cardiovascular disease. The purpose of this study was to identify quantitative trait loci (QTL) for serum glucose and lipids in a White Duroc x Erhualian resource population. Serum glucose, glycosylated serum proteins (GSP), and serum lipid levels were measured in a total of 760 F(2) animals at 240 days. Strong positive correlations were observed between total cholesterol (TC) and low-density-lipoprotein cholesterol (LDL-C)/high-density-lipoprotein cholesterol (HDL-C). A whole-genome scan was performed with 194 microsatellites covering the pig genome across the entire resource population, revealing 2 QTL for serum glucose and 15 QTL for serum lipids. Of them, three 1% genome-wide significant QTL were identified for LDL-C, TC, and triglycerides (TG) in an adjacent region (67-73 cM) on chromosome 2 (SSC2), and the QTL for LDL-C showed the largest effect with a 95% confidence interval of 5 cM. Another 1% genome-wide significant QTL was found for LDL-C at 87 cM on SSC8. Other QTL showed 5% genome-wide significant or suggestive effects on SSC4, 5, 7, 9, 11, 14, and 15. In total, five significant QTL for serum lipids and a suggestive QTL for GSP on SSC4 were identified for the first time in pigs. Most of the identified QTL are homologous to the previously reported QTL for serum lipids in humans and mice. As correlated traits, QTL for TC and LDL-C were always located in the same genomic regions. The results shed new light on studies of human atherosclerosis and cardiovascular-related diseases.

Baseline erythroid indices are increasingly involved as risk factors for common complex diseases in humans. However, little is known about the genetic architecture of baseline erythroid traits in pigs. In this study, hematocrit (Hct), hemoglobin (Hgb), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), mean corpuscular volume (MCV), red blood cell (RBC), and red cell distribution width (RDW) were measured in 1420 (day 18), 1410 (day 46), and 1033 (day 240) F(2) pigs from a White Duroc x Erhualian intercross resource population. The entire resource population was genotyped for 183 microsatellite loci across the pig genome, and the quantitative trait loci (QTL) analysis was performed for all erythroid-related traits measured with QTL Express based on a least-squares method. A total of 101 QTL, including 46 genome-wide significant QTL and 55 chromosome-wide significant QTL, regulating erythroid traits were found on all pig chromosomes (SSC) except for SSC15 and SSC18. The genome-wide significant QTL were mainly localized on SSC1, 7, 8, 10, and X. These results confirmed most of QTL previously identified in the swine. More importantly, this study detected age-specific QTL for baseline erythroid traits in pigs for the first time. Notably, the QTL for MCV and MCH on day 18 on SSC8 with small intervals of 3 and 4 cM, respectively, provided a good starting point for identifying causal genes underlying MCV and MCH in the future.

Lactation, hair development and homeothermy are characteristic evolutionary features that define mammals from other vertebrate species. Here we describe the discovery of two autosomal dominant mutations with antagonistic, pleiotropic effects on all three of these biological processes, mediated through the prolactin signalling pathway. Most conspicuously, mutations in prolactin (PRL) and its receptor (PRLR) have an impact on thermoregulation and hair morphology phenotypes, giving prominence to this pathway outside of its classical roles in lactation., The hormone prolactin is a known modulator of mammalian lactation and hair growth. Here, the authors describe two dominant mutations in bovine prolactin and its receptor, demonstrating antagonistic effects on these traits and highlighting a role for this pathway in sweat gland function and thermoregulation.

Fertility is one of the most important traits in dairy cattle, and has been steadily declining over the last decades. We herein use state-of-the-art genomic tools, including high-throughput SNP genotyping and next-generation sequencing, to identify a 3.3 Kb deletion in the FANCI gene causing the brachyspina syndrome (BS), a rare recessive genetic defect in Holstein dairy cattle. We determine that despite the very low incidence of BS (

Background Elucidation of the pig transcriptome is essential for interpreting functional elements of the genome and understanding the genetic architecture of complex traits such as fat deposition, metabolism and growth. Results Here we used massive parallel high-throughput RNA sequencing to generate a high-resolution map of the porcine mRNA and miRNA transcriptome in liver, longissimus dorsi and abdominal fat from two full-sib F2 hybrid pigs with segregated phenotypes on growth, blood physiological and biochemical parameters, and fat deposition. We obtained 8,508,418-10,219,332 uniquely mapped reads that covered 78.0% of the current annotated transcripts and identified 48,045-122,931 novel transcript fragments, which constituted 17,085-29,499 novel transcriptional active regions in six tested samples. We found that about 18.8% of the annotated genes showed alternative splicing patterns, and alternative 3' splicing is the most common type of alternative splicing events in pigs. Cross-tissue comparison revealed that many transcriptional events are tissue-differential and related to important biological functions in their corresponding tissues. We also detected a total of 164 potential novel miRNAs, most of which were tissue-specifically identified. Integrated analysis of genome-wide association study and differential gene expression revealed interesting candidate genes for complex traits, such as IGF2, CYP1A1, CKM and CES1 for heart weight, hemoglobin, pork pH value and serum cholesterol, respectively. Conclusions This study provides a global view of the complexity of the pig transcriptome, and gives an extensive new knowledge about alternative splicing, gene boundaries and miRNAs in pigs. Integrated analysis of genome wide association study and differential gene expression allows us to find important candidate genes for porcine complex traits.