TreeFam: a curated database of phylogenetic trees of animal gene families

Genome-Wide Identification of Specific Genetic Loci Common to Sheep and Goat

Sheep and goat may become carriers of some zoonotic diseases. They are important livestock and experimental model animals for human beings. The fast and accurate identification of genetic materials originating from sheep and goat can prevent and inhibit the spread of some zoonotic diseases, monitor market product quality, and maintain the stability of animal husbandry and food industries. This study proposed a methodology for identifying sheep and goat common specific sites from a genome-wide perspective. A total of 150 specific sites were selected from three data sources, including the coding sequences of single copy genes from nine species (sheep, goat, cow, pig, dog, horse, human, mouse, and chicken), the dbSNPs for these species, and human 100-way alignment data. These 150 sites exhibited low intraspecific heterogeneity in the resequencing data of 1450 samples from five species (sheep, goat, cow, pig, and chicken) and high interspecific divergence in the human 100-way alignment data after quality control. The results were proven to be reliable at the data level. Using the process proposed in this study, specific sites of other species can be screened, and genome-level species identification can be performed using the screened sites.

Adenylate kinase phosphate energy shuttle underlies energetic communication in flagellar axonemes

The complexities of energy transfer mechanisms in the flagella of mammalian sperm flagella have been intensively investigated and demonstrate significant diversity across species. Enzymatic shuttles, particularly adenylate kinase (AK) and creatine kinase (CK), are pivotal in the efficient transfer of intracellular ATP, showing distinct tissue- and species-specificity. Here, the expression profiles of AK and CK were investigated in mice and found to fall into four subgroups, of which Subgroup III AKs were observed to be unique to the male reproductive system and conserved across chordates. Both AK8 and AK9 were found to be indispensable to male reproduction after analysis of an infertile male cohort. Knockout mouse models showed that AK8 and AK9 were central to promoting sperm motility. Immunoprecipitation combined with mass spectrometry revealed that AK8 and AK9 interact with the radial spoke (RS) of the axoneme. Examination of various human and mouse sperm samples with substructural damage, including the presence of multiple RS subunits, showed that the head of radial spoke 3 acts as an adapter for AK9 in the flagellar axoneme. Using an ATP probe together with metabolomic analysis, it was found that AK8 and AK9 cooperatively regulated ATP transfer in the axoneme, and were concentrated at sites associated with energy consumption in the flagellum. These findings indicate a novel function for RS beyond its structural role, namely, the regulation of ATP transfer. In conclusion, the results expand the functional spectrum of AK proteins and suggest a fresh model regarding ATP transfer within mammalian flagella.

Manipulating Myc for reparative regeneration

The Myc family of proto-oncogenes is a key node for the signal transduction of external pro-proliferative signals to the cellular processes required for development, tissue homoeostasis maintenance, and regeneration across evolution. The tight regulation of Myc synthesis and activity is essential for restricting its oncogenic potential. In this review, we highlight the central role that Myc plays in regeneration across the animal kingdom (from Cnidaria to echinoderms to Chordata) and how Myc could be employed to unlock the regenerative potential of non-regenerative tissues in humans for therapeutic purposes. Mastering the fine balance of harnessing the ability of Myc to promote transcription without triggering oncogenesis may open the door to many exciting opportunities for therapeutic development across a wide array of diseases.

Haplotype-resolved chromosome-scale genomes of the Asian and African Savannah Elephants

The Proboscidea, which includes modern elephants, were once the largest terrestrial animals among extant species. They suffered mass extinction during the Ice Age. As a unique branch on the evolutionary tree, the Proboscidea are of great significance for the study of living animals. In this study, we generate chromosome-scale and haplotype-resolved genome assemblies for two extant Proboscidea species (Asian Elephant, Elephas maximus and African Savannah Elephant, Loxodonta africana) using Pacbio, Hi-C, and DNBSEQ technologies. The assembled genome sizes of the Asian and African Savannah Elephant are 3.38 Gb and 3.31 Gb, with scaffold N50 values of 130 Mb and 122 Mb, respectively. Using Hi-C technology ~97% of the scaffolds are anchored to 29 pseudochromosomes. Additionally, we identify ~9 Mb Y-linked sequences for each species. The high-quality genome assemblies in this study provide a valuable resource for future research on ecology, evolution, biology and conservation of Proboscidea species.

Exploring the cobia (Rachycentron canadum) genome: unveiling putative male heterogametic regions and identification of sex-specific markers

BACKGROUND

Cobia (Rachycentron canadum) is the only member of the Rachycentridae family and exhibits considerable sexual dimorphism in growth rate. Sex determination in teleosts has been a long-standing basic biological question, and the molecular mechanisms of sex determination/differentiation in cobia are completely unknown.

RESULTS

Here, we reported 2 high-quality, chromosome-level annotated male and female cobia genomes with assembly sizes of 586.51 Mb (contig/scaffold N50: 86.0 kb/24.3 Mb) and 583.88 Mb (79.9 kb/22.5 Mb), respectively. Synteny inference among perciform genomes revealed that cobia and the remora Echeneis naucrates were sister groups. Further, whole-genome resequencing of 31 males and 60 females, genome-wide association study, and sequencing depth analysis identified 3 short male-specific regions within a 10.7-kb continuous genomic region on male chromosome 18, which hinted at an undifferentiated sex chromosome system with a putative XX/XY mode of sex determination in cobia. Importantly, the only 2 genes within/between the male-specific regions, epoxide hydrolase 1 (ephx1, renamed cephx1y) and transcription factor 24 (tcf24, renamed ctcf24y), showed testis-specific/biased gene expression, whereas their counterparts cephx1x and ctf24x, located in female chromosome 18, were similarly expressed in both sexes. In addition, male-specific PCR targeting the cephx1y gene revealed that this genomic feature is conserved in cobia populations from Panama, Brazil, Australia, and Japan.

CONCLUSION

The first comprehensive genomic survey presented here is a valuable resource for future studies on cobia population structure and dynamics, conservation, and evolutionary history. Furthermore, it establishes evidence of putative male heterogametic regions with 2 genes playing a potential role in the sex determination of the species, and it provides further support for the rapid evolution of sex-determining mechanisms in teleost fish.

Genetic variants in DDX53 contribute to Autism Spectrum Disorder associated with the Xp22.11 locus

Autism Spectrum Disorder (ASD) exhibits an ~4:1 male-to-female sex bias and is characterized by early-onset impairment of social/communication skills, restricted interests, and stereotyped behaviors. Disruption of the Xp22.11 locus has been associated with ASD in males. This locus includes the three-exon PTCHD1 gene, an adjacent multi-isoform long noncoding RNA (lncRNA) named PTCHD1-AS (spanning ~1Mb), and a poorly characterized single-exon RNA helicase named DDX53 that is intronic to PTCHD1-AS. While the relationship between PTCHD1/PTCHD1-AS and ASD is being studied, the role of DDX53 has not been examined, in part because there is no apparent functional murine orthologue. Through clinical testing, here, we identified 6 males and 1 female with ASD from 6 unrelated families carrying rare, predicted-damaging or loss-of-function variants in DDX53. Then, we examined databases, including the Autism Speaks MSSNG and Simons Foundation Autism Research Initiative, as well as population controls. We identified 24 additional individuals with ASD harboring rare, damaging DDX53 variations, including the same variants detected in two families from the original clinical analysis. In this extended cohort of 31 participants with ASD (28 male, 3 female), we identified 25 mostly maternally-inherited variations in DDX53, including 18 missense changes, 2 truncating variants, 2 in-frame variants, 2 deletions in the 3' UTR and 1 copy number deletion. Our findings in humans support a direct link between DDX53 and ASD, which will be important in clinical genetic testing. These same autism-related findings, coupled with the observation that a functional orthologous gene is not found in mouse, may also influence the design and interpretation of murine-modelling of ASD.

Approaches to increase the validity of gene family identification using manual homology search tools

Identifying homologs is an important process in the analysis of genetic patterns underlying traits and evolutionary relationships among species. Analysis of gene families is often used to form and support hypotheses on genetic patterns such as gene presence, absence, or functional divergence which underlie traits examined in functional studies. These analyses often require precise identification of all members in a targeted gene family. Manual pipelines where homology search and orthology assignment tools are used separately are the most common approach for identifying small gene families where accurate identification of all members is important. The ability to curate sequences between steps in manual pipelines allows for simple and precise identification of all possible gene family members. However, the validity of such manual pipeline analyses is often decreased by inappropriate approaches to homology searches including too relaxed or stringent statistical thresholds, inappropriate query sequences, homology classification based on sequence similarity alone, and low-quality proteome or genome sequences. In this article, we propose several approaches to mitigate these issues and allow for precise identification of gene family members and support for hypotheses linking genetic patterns to functional traits.

Autoregulatory control of mitochondrial glutathione homeostasis

Mitochondria must maintain adequate amounts of metabolites for protective and biosynthetic functions. However, how mitochondria sense the abundance of metabolites and regulate metabolic homeostasis is not well understood. In this work, we focused on glutathione (GSH), a critical redox metabolite in mitochondria, and identified a feedback mechanism that controls its abundance through the mitochondrial GSH transporter, SLC25A39. Under physiological conditions, SLC25A39 is rapidly degraded by mitochondrial protease AFG3L2. Depletion of GSH dissociates AFG3L2 from SLC25A39, causing a compensatory increase in mitochondrial GSH uptake. Genetic and proteomic analyses identified a putative iron-sulfur cluster in the matrix-facing loop of SLC25A39 as essential for this regulation, coupling mitochondrial iron homeostasis to GSH import. Altogether, our work revealed a paradigm for the autoregulatory control of metabolic homeostasis in organelles.

Unravelling the genomic features, phylogeny and genetic basis of tooth ontogenesis in Characiformes through analysis of four genomes

Characiformes is a diverse and evolutionarily significant order of freshwater fish encompassing over 2,300 species. Despite its diversity, our understanding of Characiformes' evolutionary relationships and adaptive mechanisms is limited due to insufficient genome sequences. In this study, we sequenced and assembled the genomes of four Characiformes species, three of which were chromosome-level assemblies. Our analyses revealed dynamic changes in gene family evolution, repeat sequences and variations in chromosomal collinearity within these genomes. With the assembled genomes, we were not only able to elucidate the evolutionary relationship of the four main orders in Otophysi but also indicated Characiformes as the paraphyletic group. Comparative genomic analysis with other available fish genomes shed light on the evolution of genes related to tooth development in Characiformes. Notably, variations in the copy number of secretory calcium-binding phosphoproteins (SCPP) genes were observed among different orders of Otophysi, indicating their potential contribution to the diversity of tooth types. Our study offers invaluable genome sequences and novel insights into Characiformes' evolution, paving the way for further genomic and evolutionary research in fish.

Chromosome-level genome of butterflyfish unveils genomic features of unique colour patterns and morphological traits

Chaetodontidae, known as butterflyfishes, are typical fish in coral ecosystems, exhibiting remarkable interspecific differences including body colour patterns and feeding ecology. In this study, we report genomes of three butterflyfish species (Chelmon rostratus, Chaetodon trifasciatus and Chaetodon auriga) and a closely related species from the Pomacanthidae family, Centropyge bicolour, with an average genome size of 65,611 Mb. Chelmon rostratus, comprising 24 chromosomes assembled to the chromosome level, could be served as a reference genome for butterflyfish. By conducting a collinearity analysis between butterflyfishes and several fishes, we elucidated the specific and conserved genomic features of butterflyfish, with particular emphasis on novel genes arising from tandem duplications and their potential functions. In addition to the two melanocyte-specific tyr genes commonly found in fish, we found the gene tyrp3, a new tyrosinase-related proteins gene in the reef fish, including butterflyfish and clownfish, implicating their involvement in the pigmentation diversity of fish. Additionally, we observed a tandem duplication expansion of three copies of nell1 gene in C. rostratus genome, which likely contribute to its unique jaw development and distinctive morphology of its sharp mouth. These results provided valuable genomic resources for further investigations into the genetic diversity and evolutionary adaptations of reef fish.

Chromosome-level genome assembly of the caenogastropod snail Rapana venosa

The carnivorous gastropod Rapana venosa (Valenciennes, 1846) is one of the most notorious ecological invaders worldwide. Here, we present the first high-quality chromosome-scale reference R. venosa genome obtained via PacBio sequencing, Illumina paired-end sequencing, and high-throughput chromosome conformation capture scaffolding. The assembled genome has a size of 2.30 Gb, with a scaffold N50 length of 64.63 Mb, and is anchored to 35 chromosomes. It contains 29,649 protein-coding genes, 77.22% of which were functionally annotated. Given its high heterozygosity (1.41%) and large proportion of repeat sequences (57.72%), it is one of the most complex genome assemblies. This chromosome-level genome assembly of R. venosa is an important resource for understanding molluscan evolutionary adaption and provides a genetic basis for its biological invasion control.

Mutations in cdon and boc affect trunk neural crest cell migration and slow-twitch muscle development in zebrafish

The transmembrane proteins cdon and boc are implicated in regulating hedgehog signaling during vertebrate development. Recent work showing roles for these genes in axon guidance and neural crest cell migration suggest that cdon and boc may play additional functions in regulating directed cell movements. We use newly generated and existing mutants to investigate a role for cdon and boc in zebrafish neural crest cell migration. We find that single mutant embryos exhibit normal neural crest phenotypes, but that neural crest migration is strikingly disrupted in double cdon;boc mutant embryos. We further show that this migration phenotype is associated with defects in the differentiation of slow-twitch muscle cells, and the loss of a Col1a1a-containing extracellular matrix, suggesting that neural crest defects may be a secondary consequence to defects in mesoderm development. Combined, our data add to a growing literature showing that cdon and boc act synergistically to promote hedgehog signaling during vertebrate development, and suggest that the zebrafish can be used to study the function of hedgehog receptor paralogs.

Divergent contributions of coding and noncoding sequences to initial high-altitude adaptation in passerine birds endemic to the Qinghai-Tibet Plateau

Early events in the evolution of an ancestral lineage can shape the adaptive patterns of descendant species, but the evolutionary mechanisms driving initial adaptation from an ancestor remain largely unexplored. High-altitude adaptations have been extensively explored from the viewpoint of protein-coding genes; however, the contribution of noncoding regions remains relatively neglected. Here, we integrate genomic and transcriptomic data to investigate adaptive evolution in the ancestor of three high-altitude snowfinch species endemic to the Qinghai-Tibet Plateau. Our genome-wide scan for adaptation in the snowfinch ancestor identifies strong adaptation signals in functions of development and metabolism for the coding genes, but in functions of the nervous system development for noncoding regions. This pattern is exclusive to the snowfinch ancestor compared to a control ancestral lineage subject to weak selection. Changes in noncoding regions in the snowfinch ancestor, especially those nearest to coding genes, may be disproportionately associated with the differential expression of genes in the brain tissue compared to other tissues. Extensive gene expression in the brain tissue can be further altered via genetic regulatory networks of transcription factors harbouring potential accelerated regulatory regions (e.g., the development-related transcription factor YEATS4). Altogether, our study provides new evidence concerning how coding and noncoding sequences work through decoupled pathways in initial adaptation to the selective pressure of high-altitude environments. The analysis highlights the idea that noncoding sequences may be promising elements in facilitating the rapid evolution and adaptation to high altitudes.

Genomic insights into the genetic basis of eagle-beak jaw, large head, and long tail in the big-headed turtle

The big-headed turtle (Platysternon megacephalum) is an endemic chelonian species in Asia. Unlike most other turtles in the world, P. megacephalum is characterized with eagle-beak jaw, large head, and long tail. Although these unique characteristics are well recognized, the underlying genetic basis remains largely elusive. Here, we performed comparative genomic analysis between P. megacephalum and other representative species, aiming to reveal the genetic basis of the unique morphological features. Our results revealed that the eagle-beak jaw is most likely enabled by combined effects of expansion of SFRP5, extraction of FGF11, and mutation of both ZFYVE16 and PAX6. Large head is supported by mutations of SETD2 and FGRF2 and copy number variations of six head circumference modulation-related genes (TGFBR2, Twist2, Rdh10, Gas1, Chst11, and SNAP25). The long tail is probably involved in a genetic network comprising Gdf11, Lin 28, and HoxC12, two of which showed a consistent expression pattern with a model organism (mice). These findings suggest that expansion, extraction, and mutation of those genes may have profound effects on unique phenotypes of P. megacephalum.

A chromosome-level genome assembly of tomato pinworm, Tuta absoluta

The tomato pinworm, Tuta absoluta, or Phthorimaea absouta, is native to South America, but quickly spread to other regions of world, including Europe, Africa, and Asia, devastating to global tomato production. However, a lack of high-quality genome resources makes it difficult to understand its high invasiveness and ecological adaptation. Here, we sequenced the genome of the tomato pinworm using Nanopore platforms, yielding a genome assembly of 564.5 Mb with contig N50 of 3.33 Mb. BUSCO analysis demonstrated that this genome assembly has a high-level completeness of 98.0% gene coverage. In total, 310 Mb are repeating sequences accounting for 54.8% of genome assembly, and 21,979 protein-coding genes are annotated. Next, we used the Hi-C technique to anchor 295 contigs to 29 chromosomes, yielding a chromosome-level genome assembly with a scaffold N50 of 20.7 Mb. In sum, the high-quality genome assembly of the tomato pinworm is a useful gene resource that contributes to a better understanding of the biological characteristics of its invasiveness and will help in developing an efficient control policy.

Phylogenomic analyses provide insights into primate evolution

Comparative analysis of primate genomes within a phylogenetic context is essential for understanding the evolution of human genetic architecture and primate diversity. We present such a study of 50 primate species spanning 38 genera and 14 families, including 27 genomes first reported here, with many from previously less well represented groups, the New World monkeys and the Strepsirrhini. Our analyses reveal heterogeneous rates of genomic rearrangement and gene evolution across primate lineages. Thousands of genes under positive selection in different lineages play roles in the nervous, skeletal, and digestive systems and may have contributed to primate innovations and adaptations. Our study reveals that many key genomic innovations occurred in the Simiiformes ancestral node and may have had an impact on the adaptive radiation of the Simiiformes and human evolution.

Haplotype-resolved Genome of Sika Deer Reveals Allele-specific Gene Expression and Chromosome Evolution

Despite the scientific and medicinal importance of diploid sika deer (Cervus nippon), its genome resources are limited and haplotype-resolved chromosome-scale assembly is urgently needed. To explore mechanisms underlying the expression patterns of the allele-specific genes in antlers and the chromosome evolution in Cervidae, we report, for the first time, a high-quality haplotype-resolved chromosome-scale genome of sika deer by integrating multiple sequencing strategies, which was anchored to 32 homologous groups with a pair of sex chromosomes (XY). Several expanded genes (RET, PPP2R1A, PPP2R1B, YWHAB, YWHAZ, and RPS6) and positively selected genes (eIF4E, Wnt8A, Wnt9B, BMP4, and TP53) were identified, which could contribute to rapid antler growth without carcinogenesis. A comprehensive and systematic genome-wide analysis of allele expression patterns revealed that most alleles were functionally equivalent in regulating rapid antler growth and inhibiting oncogenesis. Comparative genomic analysis revealed that chromosome fission might occur during the divergence of sika deer and red deer (Cervus elaphus), and the olfactory sensation of sika deer might be more powerful than that of red deer. Obvious inversion regions containing olfactory receptor genes were also identified, which arose since the divergence. In conclusion, the high-quality allele-aware reference genome provides valuable resources for further illustration of the unique biological characteristics of antler, chromosome evolution, and multi-omics research of cervid animals.

ADAD2 functions in spermiogenesis and piRNA biogenesis in mice

BACKGROUND

Adenosine deaminase domain containing 2 (ADAD2) is a testis-specific protein composed of a double-stranded RNA binding domain and a non-catalytic adenosine deaminase domain. A recent study showed that ADAD2 is indispensable for the male reproduction in mice. However, the detailed functions of ADAD2 remain elusive.

OBJECTIVES

This study aimed to investigate the cause of male sterility in Adad2 mutant mice and to understand the molecular functions of ADAD2.

MATERIALS AND METHODS

Adad2 homozygous mutant mouse lines, Adad2-/- and Adad2Δ/Δ , were generated by CRISPR/Cas9. Western blotting and immunohistochemistry were used to reveal the expression and subcellular localization of ADAD2. Co-immunoprecipitation tandem mass spectrometry was employed to determine the ADAD2-interacting proteins in mouse testes. RNA-sequencing analyses were carried out to analyze the transcriptome and PIWI-interacting RNA (piRNA) populations in wildtype and Adad2 mutant testes.

RESULTS

Adad2-/- and Adad2Δ/Δ mice exhibit male-specific sterility because of abnormal spermiogenesis. ADAD2 interacts with multiple RNA-binding proteins involved in piRNA biogenesis, including MILI, MIWI, RNF17, and YTHDC2. ADAD2 co-localizes and forms novel granules with RNF17 in spermatocytes. Ablation of ADAD2 impairs the formation of RNF17 granules, decreases the number of cluster-derived pachytene piRNAs, and increases expression of ping-pong-derived piRNAs.

DISCUSSION AND CONCLUSION

In collaboration with RNF17 and other RNA-binding proteins in spermatocytes, ADAD2 directly or indirectly functions in piRNA biogenesis.

Insights into the genetic determination of tuber shape and eye depth in potato natural population based on autotetraploid potato genome

Potato is one of the world's most important food crops, with a time-consuming breeding process. In this study, we performed a genome-wide association (GWAS) analysis of the two important traits of potato tuber shape and eye depth, using the tetraploid potato genome (2n=4x=48) as a reference. A total of 370 potatoes were divided into three subgroups based on the principal component analysis and evolutionary tree analysis. The genetic diversity within subgroups is low (5.18×10^-5, 4.36×10^-5 and 4.24×10^-5). Genome-wide linkage disequilibrium (LD) analysis showed that their LD is about 60 Kb. GWAS analysis identified that 146 significant single nucleotide polymorphism (SNP) loci at Chr01A1:34.44-35.25 Mb and Chr02A1:28.35-28.54 Mb regions are significantly associated with potato tuber shape, and that three candidate genes that might be related to potato tuber traits, PLATZ transcription factor, UTP-glucose-1-phosphate uridylyltransferase and FAR1 DNA-binding domain, are in the association region of Chr02A1. GWAS analysis identified 53 significant SNP loci at Chr05A2: 49.644-50.146 Mb and Chr06A2: 25.866-26.384 Mb regions with robust associations with potato tuber eye depth. Hydrolase and methyltransferases are present in the association region of Chr05A2, and three CYPs are present in the association region of Chr06A2. Our findings suggested that these genes are closely associated with potato tuber shape and eye depth. Our study identified molecular markers and candidate genes for improving tetraploid potato tuber shape and eye depth and provided ideas and insights for tetraploid potato breeding.

OrthoPhy: A Program to Construct Ortholog Data Sets Using Taxonomic Information

Species phylogenetic trees represent the evolutionary processes of organisms, and they are fundamental in evolutionary research. Therefore, new methods have been developed to obtain more reliable species phylogenetic trees. A highly reliable method is the construction of an ortholog data set based on sequence information of genes, which is then used to infer the species phylogenetic tree. However, although methods for constructing an ortholog data set for species phylogenetic analysis have been developed, they cannot remove some paralogs, which is necessary for reliable species phylogenetic inference. To address the limitations of current methods, we developed OrthoPhy, a program that excludes paralogs and constructs highly accurate ortholog data sets using taxonomic information dividing analyzed species into monophyletic groups. OrthoPhy can remove paralogs, detecting inconsistencies between taxonomic information and phylogenetic trees of candidate ortholog groups clustered by sequence similarity. Performance tests using evolutionary simulated sequences and real sequences of 40 bacteria revealed that the precision of ortholog inference by OrthoPhy is higher than that of existing programs. Additionally, the phylogenetic analysis of species was more accurate when performed using ortholog data sets constructed by OrthoPhy than that performed using data sets constructed by existing programs. Furthermore, we performed a benchmark test of the Quest for Orthologs using real sequence data and found that the concordance rate between the phylogenetic trees of orthologs inferred by OrthoPhy and those of species was higher than the rates obtained by other ortholog inference programs. Therefore, ortholog data sets constructed using OrthoPhy enabled a more accurate phylogenetic analysis of species than those constructed using the existing programs, and OrthoPhy can be used for the phylogenetic analysis of species even for distantly related species that have experienced many evolutionary events.

Chromosome-scale Genome Assembly of the Yellow Nutsedge (Cyperus esculentus)

The yellow nutsedge (Cyperus esculentus L. 1753) is an unconventional oil plant with oil-rich tubers, and a potential alternative for traditional oil crops. Here, we reported the first high-quality and chromosome-level genome assembly of the yellow nutsedge generated by combining PacBio HiFi long reads, Novaseq short reads, and Hi-C data. The final genome size is 225.6 Mb with an N50 of 4.3 Mb. More than 222.9 Mb scaffolds were anchored to 54 pseudochromosomes with a BUSCO score of 96.0%. We identified 76.5 Mb (33.9%) repetitive sequences across the genome. A total of 23,613 protein-coding genes were predicted in this genome, of which 22,847 (96.8%) were functionally annotated. A whole-genome duplication event was found after the divergence of Carex littledalei and Rhynchospora breviuscula, indicating the rich genetic resources of this species for adaptive evolution. Several significantly enriched GO terms were related to invasiveness of the yellow nutsedge, which may explain its plastic adaptability. In addition, several enriched Kyoto Encyclopedia of Genes and Genomes pathways and expanded gene families were closely related with substances in tubers, partially explaining the genomic basis of characteristics of this oil-rich tuber.

Chromosome-level genome assembly for takin (Budorcas taxicolor) provides insights into its taxonomic status and genetic diversity

The takin (Budorcas taxicolor) is one of the largest bovid herbivores in the subfamily Caprinae. The takin is at high risk of extinction, but its taxonomic status and genetic diversity remain unclear. In this study, we constructed the first reference genome of Bu. taxicolor using PacBio long High-Fidelity reads and Hi-C technology. The assembled genome is ~2.95 Gb with a contig N50 of 68.05 Mb, which were anchored onto 25+XY chromosomes. We found that the takin was more closely related to muskox than to other Caprinae species. Compared to the common ancestral karyotype of bovidae (2n = 60), we found the takin (2n = 52) experienced four chromosome fusions and one large translocation. Furthermore, we resequenced nine golden takins from the main distribution area, the Qinling Mountains, and identified 3.3 million single nucleotide polymorphisms. The genetic diversity of takin was very low (θπ = 0.00028 and heterozygosity =0.00038), among the lowest detected in domestic and wild mammals. Takin genomes showed a high inbreeding coefficient (FROH =0.217), suggesting severe inbreeding depression. The demographic history showed that the effective population size of takins declined significantly from ~100,000 years ago. Our results provide valuable information for protection of takins and insights into their evolution.

A genome and single-nucleus cerebral cortex transcriptome atlas of the short-finned pilot whale Globicephala macrorhynchus

Cetaceans (dolphins, whales, and porpoises) have large and anatomically sophisticated brains. To expand our understanding of the cellular makeup of cetacean brains and the similarities and divergence between the brains of cetaceans and terrestrial mammals, we report a short-finned pilot whale (Globicephala macrorhynchus) single-nucleus transcriptome atlas. To achieve this goal, we assembled a chromosome-scale reference genome spanning 2.25 Gb on 22 chromosomes and profiled the gene expression of five major anatomical cortical regions of the short-finned pilot whale by single-nucleus RNA-sequencing (snRNA-seq). We identified six major cell lineages in the cerebral cortex (excitatory neurons, inhibitory neurons, oligodendrocytes, oligodendrocyte precursor cells, astrocytes, and endothelial cells), eight molecularly distinct subclusters of excitatory neurons, and four subclusters of inhibitory neurons. Finally, a comparison of snRNA-seq data from the short-finned pilot whale, human, and rhesus macaque revealed a broadly conserved cellular makeup of brain cell types. Our study provides genomic resources and molecular insights into cetacean brain evolution.

1700029I15Rik orchestrates the biosynthesis of acrosomal membrane proteins required for sperm-egg interaction

Sperm acrosomal membrane proteins, such as Izumo sperm-egg fusion 1 (IZUMO1) and sperm acrosome-associated 6 (SPACA6), play essential roles in mammalian gamete binding or fusion. How their biosynthesis is regulated during spermiogenesis has largely remained elusive. Here, we show that 1700029I15Rik knockout male mice are severely subfertile and their spermatozoa do not fuse with eggs. 1700029I15Rik is a type-II transmembrane protein expressed in early round spermatids but not in mature spermatozoa. It interacts with proteins involved in N-linked glycosylation, disulfide isomerization, and endoplasmic reticulum (ER)-Golgi trafficking, suggesting a potential role in nascent protein processing. The ablation of 1700029I15Rik destabilizes non-catalytic subunits of the oligosaccharyltransferase (OST) complex that are pivotal for N-glycosylation. The knockout testes exhibit normal expression of sperm plasma membrane proteins, but decreased abundance of multiple acrosomal membrane proteins involved in fertilization. The knockout sperm show upregulated chaperones related to ER-associated degradation (ERAD) and elevated protein ubiquitination; strikingly, SPACA6 becomes undetectable. Our results support for a specific, 1700029I15Rik-mediated pathway underpinning the biosynthesis of acrosomal membrane proteins during spermiogenesis.

Loss of epigenetic information as a cause of mammalian aging

All living things experience an increase in entropy, manifested as a loss of genetic and epigenetic information. In yeast, epigenetic information is lost over time due to the relocalization of chromatin-modifying proteins to DNA breaks, causing cells to lose their identity, a hallmark of yeast aging. Using a system called "ICE" (inducible changes to the epigenome), we find that the act of faithful DNA repair advances aging at physiological, cognitive, and molecular levels, including erosion of the epigenetic landscape, cellular exdifferentiation, senescence, and advancement of the DNA methylation clock, which can be reversed by OSK-mediated rejuvenation. These data are consistent with the information theory of aging, which states that a loss of epigenetic information is a reversible cause of aging.

Psi promotes Drosophila wing growth via direct transcriptional activation of cell cycle targets and repression of growth inhibitors

The first characterised FUSE Binding Protein family member, FUBP1, binds single-stranded DNA to activate MYC transcription. Psi, the sole FUBP protein in Drosophila, binds RNA to regulate P-element and mRNA splicing. Our previous work revealed pro-growth functions for Psi, which depend, in part, on transcriptional activation of Myc. Genome-wide functions for FUBP family proteins in transcriptional control remain obscure. Here, through the first genome-wide binding and expression profiles obtained for a FUBP family protein, we demonstrate that, in addition to being required to activate Myc to promote cell growth, Psi also directly binds and activates stg to couple growth and cell division. Thus, Psi knockdown results in reduced cell division in the wing imaginal disc. In addition to activating these pro-proliferative targets, Psi directly represses transcription of the growth inhibitor tolkin (tok, a metallopeptidase implicated in TGFβ signalling). We further demonstrate tok overexpression inhibits proliferation, while tok loss of function increases mitosis alone and suppresses impaired cell division caused by Psi knockdown. Thus, Psi orchestrates growth through concurrent transcriptional activation of the pro-proliferative genes Myc and stg, in combination with repression of the growth inhibitor tok.

Mechanisms of sex differentiation and sex reversal in hermaphrodite fish as revealed by the Epinephelus coioides genome

Most grouper species are functional protogynous hermaphrodites, but the genetic basis and the molecular mechanisms underlying the regulation of this unique reproductive strategy remain enigmatic. In this study, we report a high-quality chromosome-level genome assembly of the representative orange-spotted grouper (Epinephelus coioides). No duplication or deletion of sex differentiation-related genes was found in the genome, suggesting that sex development in this grouper may be related to changes in regulatory sequences or environmental factors. Transcriptomic analyses showed that aromatase and retinoic acid are probably critical to promoting ovarian fate determination, and follicle-stimulating hormone triggers the female-to-male sex change. Socially controlled sex-change studies revealed that, in sex-changing fish, the brain's response to the social environment may be mediated by activation of the phototransduction cascade and the melatonin synthesis pathway. In summary, our genomic and experimental results provide novel insights into the molecular mechanisms of sex differentiation and sex change in the protogynous groupers.

MLProbs: A Data-Centric Pipeline for Better Multiple Sequence Alignment

In this paper, we explore using the data-centric approach to tackle the Multiple Sequence Alignment (MSA) construction problem. Unlike the algorithm-centric approach, which reduces the construction problem to a combinatorial optimization problem based on an abstract mathematical model, the data-centric approach explores using classification models trained from existing benchmark data to guide the construction. We identified two simple classifications to help us choose a better alignment tool and determine whether and how much to carry out realignment. We show that shallow machine-learning algorithms suffice to train sensitive models for these classifications. Based on these models, we implemented a new multiple sequence alignment pipeline, called MLProbs. Compared with 10 other popular alignment tools over four benchmark databases (namely, BAliBASE, OXBench, OXBench-X and SABMark), MLProbs consistently gives the highest TC score. More importantly, MLProbs shows non-trivial improvement for protein families with low similarity; in particular, when evaluated against the 1,356 protein families with similarity ≤ 50%, MLProbs achieves a TC score of 56.93, while the next best three tools are in the range of [55.41, 55.91] (increased by more than 1.8%). We also compared the performance of MLProbs and other MSA tools in two real-life applications - Phylogenetic Tree Construction Analysis and Protein Secondary Structure Prediction - and MLProbs also had the best performance. In our study, we used only shallow machine-learning algorithms to train our models. It would be interesting to study whether deep-learning methods can help make further improvements, so we suggest some possible research directions in the conclusion section.

Chromosome-Level Genome Assembly of the Speckled Blue Grouper (Epinephelus cyanopodus) Provides Insight into Its Adaptive Evolution

Epinephelus cyanopodus is a coral reef-dwelling grouper with important economic and ecological value and is widely distributed in the western Pacific Ocean. The lack of genomic resources for E. cyanopodus hinders its adaptive evolution and phylogeny research. We constructed the first high-quality genome of E. cyanopodus based on DNBSEQ, PacBio, and Hic sequencing technologies, with a genome size of 998.82 Mb, contig N50 of 5.855 Mb, and scaffold N50 of 41.98 Mb. More than 99.7% of contigs were anchored to 24 pseudochromosomes, and 94.2% of BUSCO genes were found in the E. cyanopodus genome, indicating a high genome assembly completeness. A total of 26,337 protein-coding genes were predicted, of which 98.77% were functionally annotated. Phylogenetic analysis showed that E. cyanopodus separated from its closely related species Epinephelus akaara about 11.5-26.5 million years ago, and the uplift of the Indo-Australian archipelago may have provided an opportunity for its rapid radiation. Moreover, several gene families associated with innate and adaptive immunity were significantly expanded in speckled blue grouper compared to other teleost genomes. Additionally, we identified several genes associated with immunity, growth and reproduction that are under positive selection in E. cyanopodus compared to other groupers, suggesting that E. cyanopodus has evolved broad adaptability in response to complex survival environment, which may provide the genetic basis for its rapid radiation. In brief, the high-quality reference genome of the speckled blue grouper provides a foundation for research on its biological traits and adaptive evolution and will be an important genetic tool to guide aquaculture and resolve its taxonomic controversies in future studies.

Functional genomics analysis reveals the evolutionary adaptation and demographic history of pygmy lorises

Lorises are a group of globally threatened strepsirrhine primates that exhibit many unusual physiological and behavioral features, including a low metabolic rate, slow movement, and hibernation. Here, we assembled a chromosome-level genome sequence of the pygmy loris (Xanthonycticebus pygmaeus) and resequenced whole genomes from 50 pygmy lorises and 6 Bengal slow lorises (Nycticebus bengalensis). We found that many gene families involved in detoxification have been specifically expanded in the pygmy loris, including the GSTA gene family, with many newly derived copies functioning specifically in the liver. We detected many genes displaying evolutionary convergence between pygmy loris and koala, including PITRM1. Significant decreases in PITRM1 enzymatic activity in these two species may have contributed to their characteristic low rate of metabolism. We also detected many evolutionarily convergent genes and positively selected genes in the pygmy loris that are involved in muscle development. Functional assays demonstrated the decreased ability of one positively selected gene, MYOF, to up-regulate the fast-type muscle fiber, consistent with the lower proportion of fast-twitch muscle fibers in the pygmy loris. The protein product of another positively selected gene in the pygmy loris, PER2, exhibited weaker binding to the key circadian core protein CRY, a finding that may be related to this species' unusual circadian rhythm. Finally, population genomics analysis revealed that these two extant loris species, which coexist in the same habitat, have exhibited an inverse relationship in terms of their demography over the past 1 million years, implying strong interspecies competition after speciation.

Genomics and transcriptomics reveal new molecular mechanism of vibriosis resistance in fish

Infectious diseases have caused dramatic production decline and economic loss for fish aquaculture. However, the poor understanding of fish disease resistance severely hampered disease prevention. Chinese tongue sole (Cynoglossus semilaevis) is an important economic flatfish suffering from vibriosis. Here we used genomic, transcriptomic and experimental approaches to investigate the molecular genetic mechanisms underlying fish vibriosis resistance. A genome-wide comparison revealed that the genes under selective sweeps were enriched for glycosaminoglycan (GAG) chondroitin sulfate (CS)/dermatan sulfate (DS) metabolism. Transcriptomic analyses prioritized synergic gene expression patterns in this pathway, which may lead to an increased CS/DS content in the resistant family. Further experimental evidence showed that carbohydrate sulfotransferases 12 (Chst12), a key enzyme for CS/DS biosynthesis, has a direct antibacterial activity. To the best of our knowledge, this is the first report that the chst12 gene has a bactericidal effect. In addition, CS/DS is a major component of the extracellular matrix (ECM) and the selection signatures and fine-tuned gene expressions of ECM-receptor interaction genes indicated a modification in the ECM structure with an enhancement of the barrier function. Furthermore, functional studies conducted on Col6a2, encoding a collagen gene which constitutes the ECM, pointed to that it may act as a cellular receptor for Vibrio pathogens, thus plays an important role for the Vibrio invasion. Taken together, these findings provide new insights into the molecular protective mechanism underlying vibriosis resistance in fish, which offers crucial genomic resources for the resistant germplasm breeding and infectious disease control in fish culturing.

Integration of multi-omics data reveals cis-regulatory variants that are associated with phenotypic differentiation of eastern from western pigs

Background

The genetic mechanisms that underlie phenotypic differentiation in breeding animals have important implications in evolutionary biology and agriculture. However, the contribution of cis-regulatory variants to pig phenotypes is poorly understood. Therefore, our aim was to elucidate the molecular mechanisms by which non-coding variants cause phenotypic differences in pigs by combining evolutionary biology analyses and functional genomics.

Results

We obtained a high-resolution phased chromosome-scale reference genome with a contig N50 of 18.03 Mb for the Luchuan pig breed (a representative eastern breed) and profiled potential selective sweeps in eastern and western pigs by resequencing the genomes of 234 pigs. Multi-tissue transcriptome and chromatin accessibility analyses of these regions suggest that tissue-specific selection pressure is mediated by promoters and distal cis-regulatory elements. Promoter variants that are associated with increased expression of the lysozyme (LYZ) gene in the small intestine might enhance the immunity of the gastrointestinal tract and roughage tolerance in pigs. In skeletal muscle, an enhancer-modulating single-nucleotide polymorphism that is associated with up-regulation of the expression of the troponin C1, slow skeletal and cardiac type (TNNC1) gene might increase the proportion of slow muscle fibers and affect meat quality.

Conclusions

Our work sheds light on the molecular mechanisms by which non-coding variants shape phenotypic differences in pigs and provides valuable resources and novel perspectives to dissect the role of gene regulatory evolution in animal domestication and breeding.

Chromosome-level genome assembly of Monochamus saltuarius reveals its adaptation and interaction mechanism with pine wood nematode

Monochamus saltuarius (Coleoptera: Cerambycidae) was reported as the vector beetle of the pine wood nematode (PWN, Bursaphelenchus xylophilus) in Japan and Europe. It was first reported to transmitted the PWN to native Pinus species in 2018 in Liaoning Province, China. However, the lack of genomic resources has limited the in-depth understanding of its interspecific relationship with PWN. Here, we obtained a chromosome-level reference genome of M. saltuarius combining Illumina, Nanopore and Hi-C sequencing technologies. We assembled the scaffolds into ten chromosomes (including an X chromosome) and obtained a 682.23 Mb chromosome-level genome with a N50 of 73.69 Mb. In total, 427.67 Mb (62.69 %) repeat sequences were identified and 14, 492 protein-coding genes were predicted, of which 93.06 % were annotated. We described the mth/mthl, P450, OBP and OR gene families associated with the vector beetle's development and resistance, as well as the host selection and adaptation, which serve as a valuable resource for understanding the host adaptation in insects during evolution. This high quality reference genome of M. saltuarius also provide new avenues for researching the mechanism of this synergistic damage between vector beetles and PWN.

Comparison of buckwheat genomes reveals the genetic basis of metabolomic divergence and ecotype differentiation

Golden buckwheat (Fagopyrum dibotrys or Fagopyrum cymosum) and Tartary buckwheat (Fagopyrum tataricum) belong to the Polygonaceae and the Fagopyrum genus is rich in flavonoids. Golden buckwheat is a wild relative of Tartary buckwheat, yet golden buckwheat is a traditional Chinese herbal medicine and Tartary buckwheat is a food crop. The genetic basis of adaptive divergence between these two buckwheats is poorly understood. Here, we assembled a high-quality chromosome-level genome of golden buckwheat and found a one-to-one syntenic relationship with the chromosomes of Tartary buckwheat. Two large inversions were identified that differentiate golden buckwheat and Tartary buckwheat. Metabolomic and genetic comparisons of golden buckwheat and Tartary buckwheat indicate an amplified copy number of FdCHI, FdF3H, FdDFR, and FdLAR gene families in golden buckwheat, and a parallel increase in medicinal flavonoid content. Resequencing of 34 wild golden buckwheat accessions across the two morphologically distinct ecotypes identified candidate genes, including FdMYB44 and FdCRF4, putatively involved in flavonoid accumulation and differentiation of plant architecture, respectively. Our comparative genomic study provides abundant genomic resources of genomic divergent variation to improve buckwheat with excellent nutritional and medicinal value.

Chromosome-level genome assembly and population genomic analyses provide insights into adaptive evolution of the red turpentine beetle, Dendroctonus valens

BACKGROUND

Biological invasions are responsible for substantial environmental and economic losses. The red turpentine beetle (RTB), Dendroctonus valens LeConte, is an important invasive bark beetle from North America that has caused substantial tree mortality in China. The lack of a high-quality reference genome seriously limits deciphering the extent to which genetic adaptions resulted in a secondary pest becoming so destructive in its invaded area.

RESULTS

Here, we present a 322.41 Mb chromosome-scale reference genome of RTB, of which 98% of assembled sequences are anchored onto fourteen linkage groups including the X chromosome with a N50 size of 24.36 Mb, which is significantly greater than other Coleoptera species. Repetitive sequences make up 45.22% of the genome, which is higher than four other Coleoptera species, i.e., Mountain pine beetle Dendroctonus ponderosae, red flour beetle Tribolium castaneum, blister beetle Hycleus cichorii, and Colorado potato beetle Leptinotarsa decemlineata. We identify rapidly expanded gene families and positively selected genes in RTB, which may be responsible for its rapid environmental adaptation. Population genetic structure of RTB was revealed by genome resequencing of geographic populations in native and invaded regions, suggesting substantial divergence of the North American population and illustrates the possible invasion and spread route in China. Selective sweep analysis highlighted the enhanced ability of Chinese populations in environmental adaptation.

CONCLUSIONS

Overall, our high-quality reference genome represents an important resource for genomics study of invasive bark beetles, which will facilitate the functional study and decipher mechanism underlying invasion success of RTB by integrating the Pinus tabuliformis genome.

De novo genome assembly of Bradysia cellarum (Diptera: Sciaridae), a notorious pest in traditional special vegetables in China

Bradysia cellarum (Diptera: Sciaridae) is a destructive vegetable insect pest infesting more than 30 species of host plants from seven families in Asia and Europe. B. cellarum causes grave problems in Chinese chive, which originated in China and is cultivated widely in East Asia. The B. cellarum infestation results in economic losses and subsequent severe food safety problems in farm productions, insecticide resistance and environmental pollution. The genomic and molecular information of B. cellarum to delineate the biological features, insecticide resistance, evolution remains poorly understood. Herein, we decode the whole genome of B. cellarum to delineate the underlying molecular mechanisms causing insecticide resistance. We constructed a highly reliable genome for B. cellarum using PacBio, Illumina and 10X Genomics sequencing platforms. The genome size of B. cellarum was 375.91 Mb with a contig N50 of 1.57 Mb. A total of 16,231 genes were identified, among which 93.8% were functionally annotated, and 42.06% were repeat sequences. According to phylogenetic analysis, B. cellarum diverged from the common ancestor of Drosophila melanogaster and Musca domestica ~139.3-191.0 million years ago. Moreover, some important genes responsible for significant insecticide resistance, such as cytochrome P450s, ABC transporters and those involved in glutathione metabolism, were expanded in B. cellarum. We assembled a high-quality B. cellarum genome to provide valuable insights into their life history strategies, insecticide resistance and biological behaviours. It also lays the foundation for exploring gene structure and functional evolution, as well as comparative genomics of B. cellarum and other model insect species.

Missense Variants Reveal Functional Insights Into the Human ARID Family of Gene Regulators

Missense variants are alterations to protein coding sequences that result in amino acid substitutions. They can be deleterious if the amino acid is required for maintaining structure or/and function, but are likely to be tolerated at other sites. Consequently, missense variation within a healthy population can mirror the effects of negative selection on protein structure and function, such that functional sites on proteins are often depleted of missense variants. Advances in high-throughput sequencing have dramatically increased the sample size of available human variation data, allowing for population-wide analysis of selective pressures. In this study, we developed a convenient set of tools, called 1D-to-3D, for visualizing the positions of missense variants on protein sequences and structures. We used these tools to characterize human homologues of the ARID family of gene regulators. ARID family members are implicated in multiple cancer types, developmental disorders, and immunological diseases but current understanding of their mechanistic roles is incomplete. Combined with phylogenetic and structural analyses, our approach allowed us to characterise sites important for protein-protein interactions, histone modification recognition, and DNA binding by the ARID proteins. We find that comparing missense depletion patterns among paralogs can reveal sub-functionalization at the level of domains. We propose that visualizing missense variants and their depletion on structures can serve as a valuable tool for complementing evolutionary and experimental findings.

Genomic signatures of high-altitude adaptation and chromosomal polymorphism in geladas

Primates have adapted to numerous environments and lifestyles, but very few species are native to high elevations. Here, we investigated high-altitude adaptations in the gelada (Theropithecus gelada), a monkey endemic to the Ethiopian Plateau. We examined genome-wide variation in conjunction with measurements of hematological and morphological traits. Our new gelada reference genome is highly intact and assembled at chromosome-length levels. Unexpectedly, we identified a chromosomal polymorphism in geladas that could potentially contribute to reproductive barriers between populations. Compared to baboons at low altitude, we found that high-altitude geladas exhibit significantly expanded chest circumferences, potentially allowing for greater lung surface area for increased oxygen diffusion. We identified gelada-specific amino acid substitutions in the alpha-chain subunit of adult hemoglobin but found that gelada hemoglobin does not exhibit markedly altered oxygenation properties compared to lowland primates. We also found that geladas at high altitude do not exhibit elevated blood hemoglobin concentrations, in contrast to the normal acclimatization response to hypoxia in lowland primates. The absence of altitude-related polycythemia suggests that geladas are able to sustain adequate tissue-oxygen delivery despite environmental hypoxia. Finally, we identified numerous genes and genomic regions exhibiting accelerated rates of evolution, as well as gene families exhibiting expansions in the gelada lineage, potentially reflecting altitude-related selection. Our findings lend insight into putative mechanisms of high-altitude adaptation while suggesting promising avenues for functional hypoxia research.

A draft genome of Drung cattle reveals clues to its chromosomal fusion and environmental adaptation

Drung cattle (Bos frontalis) have 58 chromosomes, differing from the Bos taurus 2n = 60 karyotype. To date, its origin and evolution history have not been proven conclusively, and the mechanisms of chromosome fusion and environmental adaptation have not been clearly elucidated. Here, we assembled a high integrity and good contiguity genome of Drung cattle with 13.7-fold contig N50 and 4.1-fold scaffold N50 improvements over the recently published Indian mithun assembly, respectively. Speciation time estimation and phylogenetic analysis showed that Drung cattle diverged from Bos taurus into an independent evolutionary clade. Sequence evidence of centromere regions provides clues to the breakpoints in BTA2 and BTA28 centromere satellites. We furthermore integrated a circulation and contraction-related biological process involving 43 evolutionary genes that participated in pathways associated with the evolution of the cardiovascular system. These findings may have important implications for understanding the molecular mechanisms of chromosome fusion, alpine valleys adaptability and cardiovascular function.

New data and collaborations at the Saccharomyces Genome Database: updated reference genome, alleles, and the Alliance of Genome Resources

Saccharomyces cerevisiae is used to provide fundamental understanding of eukaryotic genetics, gene product function, and cellular biological processes. Saccharomyces Genome Database (SGD) has been supporting the yeast research community since 1993, serving as its de facto hub. Over the years, SGD has maintained the genetic nomenclature, chromosome maps, and functional annotation, and developed various tools and methods for analysis and curation of a variety of emerging data types. More recently, SGD and six other model organism focused knowledgebases have come together to create the Alliance of Genome Resources to develop sustainable genome information resources that promote and support the use of various model organisms to understand the genetic and genomic bases of human biology and disease. Here we describe recent activities at SGD, including the latest reference genome annotation update, the development of a curation system for mutant alleles, and new pages addressing homology across model organisms as well as the use of yeast to study human disease.

A systematic pan-cancer study demonstrates the oncogenic function of heterogeneous nuclear ribonucleoprotein C

Although complex links between heterogeneous nuclear ribonucleoprotein C (HNRNPC) and numerous types of cancer have been shown in both cell and animal models, a comprehensive pan-cancer investigation on the features and activities of HNRNPC is still lacking. Based on the Cancer Genome Atlas and Gene Expression Omnibus datasets, we investigated the possible oncogenic effects of HNRNPC in thirty-three cancers. HNRNPC expression was detected in the majority of cancers, and its expression level was shown to be significantly linked with cancer patient prognosis. HNRNPC increased the phosphorylation of S220, which was detected in various cancers, including ovarian cancer and colon cancer. HNRNPC expression was also shown to be related to cancer-associated cell infiltration, most notably in uveal melanoma, testicular germ cell tumors, and thymoma. Additionally, the signaling pathway for vascular endothelial growth factors and RNA transport were implicated in HNRNPC's functioning processes. In short, HNRNPC may further influence cancer progression through gene mutation, protein phosphorylation, cancer associated fibroblasts infiltration and related molecular pathways. This work was intended to provide a relatively thorough knowledge of the oncogenic activities of HNRNPC across a variety of tumor types by performing a systematic pan-cancer investigation.

Chromosome-Scale Genome of Masked Palm Civet (Paguma larvata) Shows Genomic Signatures of Its Biological Characteristics and Evolution

The masked palm civet (Paguma larvata) is a small carnivore with distinct biological characteristics, that likes an omnivorous diet and also serves as a vector of pathogens. Although this species is not an endangered animal, its population is reportedly declining. Since the severe acute respiratory syndrome (SARS) epidemic in 2003, the public has been particularly concerned about this species. Here, we present the first genome of the P. larvata, comprising 22 chromosomes assembled using single-tube long fragment read (stLFR) and Hi-C technologies. The genome length is 2.41 Gb with a scaffold N50 of 105.6 Mb. We identified the 107.13 Mb X chromosome and one 1.34 Mb Y-linked scaffold and validated them by resequencing 45 P. larvata individuals. We predicted 18,340 protein-coding genes, among which 18,333 genes were functionally annotated. Interestingly, several biological pathways related to immune defenses were found to be significantly expanded. Also, more than 40% of the enriched pathways on the positively selected genes (PSGs) were identified to be closely related to immunity and survival. These enriched gene families were inferred to be essential for the P. larvata for defense against the pathogens. However, we did not find a direct genomic basis for its adaptation to omnivorous diet despite multiple attempts of comparative genomic analysis. In addition, we evaluated the susceptibility of the P. larvata to the SARS-CoV-2 by screening the RNA expression of the ACE2 and TMPRSS2/TMPRSS4 genes in 16 organs. Finally, we explored the genome-wide heterozygosity and compared it with other animals to evaluate the population status of this species. Taken together, this chromosome-scale genome of the P. larvata provides a necessary resource and insights for understanding the genetic basis of its biological characteristics, evolution, and disease transmission control.

Distal regulation, silencers, and a shared combinatorial syntax are hallmarks of animal embryogenesis

The chromatin environment plays a central role in regulating developmental gene expression in metazoans. Yet, the ancestral regulatory landscape of metazoan embryogenesis is unknown. Here, we generate chromatin accessibility profiles for six embryonic, plus larval and adult stages in the sponge Amphimedon queenslandica. These profiles are reproducible within stages, reflect histone modifications, and identify transcription factor (TF) binding sequence motifs predictive of cis-regulatory elements operating during embryogenesis in other metazoans, but not the unicellular relative Capsaspora. Motif analysis of chromatin accessibility profiles across Amphimedon embryogenesis identifies three major developmental periods. As in bilaterian embryogenesis, early development in Amphimedon involves activating and repressive chromatin in regions both proximal and distal to transcription start sites. Transcriptionally repressive elements (“silencers”) are prominent during late embryogenesis. They coincide with an increase in cis-regulatory regions harboring metazoan TF binding motifs, as well as an increase in the expression of metazoan-specific genes. Changes in chromatin state and gene expression in Amphimedon suggest the conservation of distal enhancers, dynamically silenced chromatin, and TF-DNA binding specificity in animal embryogenesis.

A Chromosome-Level Genome Assembly of Yellowtail Kingfish (Seriola lalandi)

Yellowtail kingfish (Seriola lalandi) is a pelagic marine piscivore with a circumglobal distribution. It is particularly suitable for open ocean aquaculture owing to its large body size, fast swimming, rapid growth, and high economic value. A high-precision genome is of great significance for future genetic breeding research and large-scale aquaculture in the open ocean. PacBio, Illumina, and Hi-C data were combined to assemble chromosome-level reference genome with the size of 648.34 Mb (contig N50: 28.52 Mb). 175 contigs was anchored onto 24 chromosomes with lengths ranging from 12.28 to 34.59 Mb, and 99.79% of the whole genome sequence was covered. The BUSCOs of genome and gene were 94.20 and 95.70%, respectively. Gene families associated with adaptive behaviors, such as olfactory receptors and HSP70 gene families, expanded in the genome of S. lalandi. An analysis of selection pressure revealed 652 fast-evolving genes, among which mkxb, popdc2, dlx6, and ifitm5 may be related to rapid growth traits. The data generated in this study provide a valuable resource for understanding the genetic basis of S. lalandi traits.

A high-quality chromosome-level genome of the endangered roughskin sculpin provides insights into its evolution and adaptation

The cottids (Cottidae) are a taxonomically diverse and ecologically important component of many marine and freshwater ecosystems. Despite recent breakthroughs in long-read sequencing, high quality genomic resources are still limited for studies of ecological and evolutionary processes in cottids. Here we generated a high-quality, chromosome-scale genome assembly (521.26 Mb) of the catadromous roughskin sculpin (Trachidermus fasciatus Heckel) with a contig N50 of 2.93 Mb and a scaffold N50 of 24.06 Mb. Approximately 21.97% of the genome was composed of repetitive elements. A total of 21,872 protein-coding genes were predicted, of which 19,900 genes (90.98%) were functionally annotated. Phylogenetic analysis supported the validity of Scorpaenoidei and Cottioidei as two suborders of the Perciformes. Chromosome-scale collinearity analyses identified four chromosome fusions leading to the reduction of chromosome number in T. fasciatus. Gene families related to cell apoptosis and cell death were expanded and those related to immune system were contracted, suggesting that these gene families might be relevant to a host of phenotypic differences between T. fasciatus and other teleosts. Gene families associated with osmoregulation were also expanded, which might be associated with its catadromous life history. A total of 50 aging-associated genes were found to be under positive selection, which might be associated with the short lifespan of T. fasciatus. The high-quality genome assembly and annotation will promote researches into the evolution of catadromous life history and short lifespan for T. fasciatus and facilitate comparative genomic studies of cottids in the near future.

Chromosome-level genome and population genomic analysis provide insights into the evolution and environmental adaptation of Jinjiang oyster Crassostrea ariakensis

The Jinjiang oyster Crassostrea ariakensis, naturally distributing in estuarine regions with low salinity, is an important economic and ecological species in China. However, studies on its genomics and population genetics remain lacking. Here, we assembled the chromosome-level genome of a female C. ariakensis and re-sequenced 261 individuals from five locations in China representing three typical habitats. The C. ariakensis genome was 662.9 Mb with contig N50 length of 5.9 Mb using PacBio HiFi-CCS long reads, and 99.83% sequences were anchored onto 10 pseudochromosomes using Hi-C data. A total of 26,354 protein-coding genes were predicted. We identified three significantly expanded gene families which are closely associated with osmotic pressure regulation, including CDO, SLC13 and SDR. Population structure analysis revealed that the C. ariakensis from five locations were clustered into three typical groups (northern, southern and Shanghai) (K = 3) and their phylogenetic relationship was consistently correlated to their geographical distribution. Furtherly, the differentiation between northern and southern groups was clearly demonstrated by estimated population differentiation coefficient (F_ST  = 0.1154), and the PSMC distribution showed the two groups of effective population size separated at 0.1 Ma. Meanwhile gene flow from southern to Shanghai was detected. Selective sweep analysis between northern and southern group detected genes associated with heat response and salinity adaptation. This study could provide valuable genomic resources and information for further research on the molecular evolution, genetic breeding, biological function and evolutionary adaptation of C. ariakensis.

Comparable Number of Genes Having Experienced Positive Selection among Great Ape Species

Simple Summary

It is of great interest to quantify adaptive evolution in human lineage by studying genes under positive selection, since these genes could reveal insights into our own adaptive evolutionary history compared to our closely related species and often these genes are functionally important. We used the great apes as the subjects to detect gene-level adaptive evolution signals in all the great ape lineages and investigated the evolutionary patterns and functional relevance of these adaptive evolution signals. Even the differences in population size among these closely related great apes have resulted in differences in their ability to remove deleterious alleles and to adapt to changing environments, we found that they experienced comparable numbers of positive selection. Notably, we identified several genes that offer insights into great ape and human evolution. For example, SOD1, a gene associated with aging in humans, experienced positive selection in the common ancestor of the great ape and this positive selection may contribute to the aging evolution in great apes. Overall, an updated list of positively selected genes reported by this study not only informs us of adaptive evolution during great ape evolution, but is also helpful to the further study of non-human primate models for disease and other fields.

Abstract

Alleles that cause advantageous phenotypes with positive selection contribute to adaptive evolution. Investigations of positive selection in protein-coding genes rely on the accuracy of orthology, models, the quality of assemblies, and alignment. Here, based on the latest genome assemblies and gene annotations, we present a comparative analysis on positive selection in four great ape species and identify 211 high-confidence positively selected genes (PSGs). Even the differences in population size among these closely related great apes have resulted in differences in their ability to remove deleterious alleles and to adapt to changing environments, we found that they experienced comparable numbers of positive selection. We also uncovered that more than half of multigene families exhibited signals of positive selection, suggesting that imbalanced positive selection resulted in the functional divergence of duplicates. Moreover, at the expression level, although positive selection led to a more non-uniform pattern across tissues, the correlation between positive selection and expression patterns is diverse. Overall, this updated list of PSGs is of great significance for the further study of the phenotypic evolution in great apes.

Chromosome-scale assembly reveals asymmetric paleo-subgenome evolution and targets for the acceleration of fungal resistance breeding in the nut crop, pecan

Pecan (Carya illinoinensis) is a tree nut crop of worldwide economic importance that is rich in health-promoting factors. However, pecan production and nut quality are greatly challenged by environmental stresses such as the outbreak of severe fungal diseases. Here, we report a high-quality, chromosome-scale genome assembly of the controlled-cross pecan cultivar 'Pawnee' constructed by integrating Nanopore sequencing and Hi-C technologies. Phylogenetic and evolutionary analyses reveal two whole-genome duplication (WGD) events and two paleo-subgenomes in pecan and walnut. Time estimates suggest that the recent WGD event and considerable genome rearrangements in pecan and walnut account for expansions in genome size and chromosome number after the divergence from bayberry. The two paleo-subgenomes differ in size and protein-coding gene sets. They exhibit uneven ancient gene loss, asymmetrical distribution of transposable elements (especially LTR/Copia and LTR/Gypsy), and expansions in transcription factor families (such as the extreme pecan-specific expansion in the far-red impaired response 1 family), which are likely to reflect the long evolutionary history of species in the Juglandaceae. A whole-genome scan of resequencing data from 86 pecan scab-associated core accessions identified 47 chromosome regions containing 185 putative candidate genes. Significant changes were detected in the expression of candidate genes associated with the chitin response pathway under chitin treatment in the scab-resistant and scab-susceptible cultivars 'Excell' and 'Pawnee'. These findings enable us to identify key genes that may be important susceptibility factors for fungal diseases in pecan. The high-quality sequences are valuable resources for pecan breeders and will provide a foundation for the production and quality improvement of tree nut crops.