Fatty acid composition in muscle is an important factor that affects the nutritive value and taste of pork. To investigate the genetic architecture of fatty acid composition of pork, we measured fatty acid contents in longissimus dorsi muscle of 1244 pigs from three divergent populations and conducted genome-wide association studies (GWAS) for fatty acid contents. We detected 26 genome-wide significant quantitative trait loci (QTL) on eight chromosomes (SSC for Sus scrofa) for eight fatty acids. These loci not only replicated previously reported QTL for C18:0 on SSC14 and C20:0 on SSC16, but also included several novel QTL such as those for C20:1 on SSC7, C14:0 on SSC9, and C14:0, C16:0 and C16:1 on SSC12. Furthermore, we performed a meta-analysis of GWAS on five populations, including the three populations that were investigated in this study and two additional populations that we had previously examined. This enhanced the strength of the associations detected between fatty acid composition and several marker loci, especially for those for C18:0 on SSC14 and C20:0 on SSC16. The genes ELOVL5, ELOVL6, ELOVL7, FASN, SCD and THRSP, which have functions that are directly relevant to fatty acid metabolism, are proximal to the top associated markers at six significant QTL. The findings improve our understanding of the genetic architecture of fatty acid composition in pork and contribute to further fine-map and characterize genes that influence fatty acid composition.

Background: It has been shown that hematological traits are strongly associated with the metabolism and the immune system in domestic pig. However, little is known about the genetic architecture of hematological traits. To identify quantitative trait loci (QTL) controlling hematological traits, we performed single marker Genome-wide association studies (GWAS) and haplotype analysis for 15 hematological traits in 495 Chinese Sutai pigs.Results: We identified 161 significant SNPs including 44 genome-wide significant SNPs associated with 11 hematological traits by single marker GWAS. Most of them were located on SSC2. Meanwhile, we detected 499 significant SNPs containing 154 genome-wide significant SNPs associated with 9 hematological traits by haplotype analysis. Most of the identified loci were located on SSC7 and SSC9.Conclusions: We detected 4 SNPs with pleiotropic effects on SSC2 by single marker GWAS and (or) on SSC7 by haplotype analysis. Furthermore, through checking the gene functional annotations, positions and their expression variation, we finally selected 7 genes as potential candidates. Specially, we found that three genes (TRIM58, TRIM26andTRIM21) of them originated from the same gene family and executed similar function of innate and adaptive immune. The findings will contribute to dissection the immune gene network, further identification of causative mutations underlying the identified QTLs and providing insights into the molecular basis of hematological trait in domestic pig.

The Betta fish displays a remarkable variety of phenotypes selected during domestication. However, the genetic basis underlying these traits remains largely unexplored. Here, we report a high-quality genome assembly and resequencing of 727 individuals representing diverse morphotypes of the Betta fish. We show that current breeds have a complex domestication history with extensive introgression with wild species. Using a genome-wide association study, we identify the genetic basis of multiple traits, including coloration patterns, the “Dumbo” phenotype with pectoral fin outgrowth, extraordinary enlargement of body size that we map to a major locus on chromosome 8, the sex determination locus that we map to dmrt1 , and the long-fin phenotype that maps to the locus containing kcnj15 . We also identify a polygenic signal related to aggression, involving multiple neural system-related genes such as esyt2 , apbb2 , and pank2 . Our study provides a resource for developing the Betta fish as a genetic model for morphological and behavioral research in vertebrates.

The Betta coccina complex is a diverse taxonomic group of fighting fish widely distributed in isolated islands in Southeast Asia. This genus is an ideal model for investigating freshwater fish evolutionary patterns and historical biogeography in the Malay Archipelago. In this study, based on principal component analysis of morphological traits, taxonomic diagnoses, and phylogenetic analysis of the mitochondrial cytochrome b gene, two new species are described from Sumatra Island, Betta iaspissp. nov. and Betta mulyadiisp. nov. The former has a distinctive black anal fin with a few red patches on the posterior half, while the latter is red and unspotted throughout, distinguishing them with their five or six subdorsal scales from other members of the Betta coccina complex. Phylogenetic analysis of the Betta coccina complex based on Cyt b further suggests that the speciation and present distributional pattern of this complex cannot be explained simply by the current geographic isolation of the Strait of Malacca, but by the connection-isolation scenario in the Pleistocene biogeographic context in Sundaland. This metapopulation of extant Betta species suggests a potential radiative evolution before the Last Glacial Maximum. These findings advance our understanding of the taxonomy and biogeographic evolution of Betta species in Southeast Asia.

The yellow drum (Nibea albiflora) is an economically important sciaenid fish in East Asian countries. In this study, we sequenced and assembled a near-complete gynogenetic yellow drum genome. We generated 45.63 Gb of Illumina short-reads and 80.27 Gb of PacBio long-reads and assembled them into a 628.01-Mb genome with a contig N50 of 4.42 Mb. Twenty-four chromosomes with a scaffold N50 of 26.73 Mb were obtained using the Hi-C analysis. We predicted a set of 27,069 protein-coding genes, of which 1,581 and 2,583 were expanded and contracted gene families, respectively. The most expanded genes were categorised into the protein binding, zinc-ion binding and ATP binding functional pathways. We built a high-density genetic linkage map that spanned 4,300.2 cM with 24 linkage groups and a resolution of 0.69 cM. The high-quality reference genome and annotated profiles that we produced will not only increase our understanding of the genetic architecture of economic traits in the yellow drum, but also help us explore the evolution and unique biological characteristics of sciaenid fishes.

We describe two new species of Parosphromenus from Indonesia based on morphological and molecular diagnoses. Parosphromenus juelinae, sp. nov., occurs on Bangka Island. Its unpaired fin coloration is similar to that of P. deissneri, but it differs from the latter in having a rounded caudal fin with a non-filamentous branched median ray and a smaller anal fin. Although the new species has the same caudal fin structure as P. bintan, it can be distinguished from the latter by its distinct unpaired fin coloration and the intense red color on the body flanks. Parosphromenus kishii, sp. nov., is found only in a single river system in Kalimantan Tengah. It is distinguished from all other congeners by the unique coloration of its caudal fin. A phylogenetic tree based on the cytochrome b (cytb) gene indicates that the two new species are distinct monophyletic groups constituting distinct phylogenetic branches from their congeners. Cytochrome b Genetic distances between Parosphromenus juelinae, sp. nov., and Parosphromenus kishii, sp. nov., and the other taxa in the phylogenetic tree range from 2.44% to 19.52% and from 8.65% to 17.28%, respectively.