Zoological Research最新文献

Mammalian scent glands mediate species-specific chemical communication, yet the mechanistic basis for convergent musk production remain incompletely understood. Forest musk deer and muskrat have independently evolved specialized musk-secreting glands, representing a striking case of convergent evolution. Through an integrated multi-omics approach, this study identified cyclopentadecanone as a shared key metabolic precursor in musk from both forest musk deer and muskrat, although downstream metabolite profiles diverged between the two lineages. Single-cell RNA sequencing revealed that these specialized apocrine glands possessed unique secretory architecture and exhibited transcriptional profiles associated with periodic musk production, distinct from those in conventional apocrine glands. Convergent features were evident at the cellular level, where acinar, ductal, and basal epithelial subtypes showed parallel molecular signatures across both taxa. Notably, acinar cells in both species expressed common genes involved in fatty acid and glycerolipid metabolism (e.g., ACSBG1, HSD17B12, HACD2, and HADHA), suggesting a conserved molecular framework for musk precursor biosynthesis. Metagenomic analysis of musk samples further revealed parallel microbial community structures dominated by Corynebacterium and enriched in lipid metabolic pathways. These findings suggest multi-level convergence in musk biosynthesis, from molecular pathways to microbial communities, providing novel insights into mammalian chemical signaling and artificial musk production.

Coat color polymorphism in domestic animals provides a robust framework for elucidating mechanisms of species adaptation, domestication, and genomic diversity. Leiqiong cattle, a representative indicine breed from southern China, are predominantly yellow-coated, although a subset exhibits a solid black phenotype. To determine the genetic basis of this variation, a genome-wide association study (GWAS) was performed in 212 Leiqiong bulls. A pronounced association signal was detected on chromosome 6 within the fifth intron of the CORIN gene, providing the first evidence of the potential influence of CORIN on bovine coat color variation. Integration of these results with publicly available genomic datasets and haplotype analyses indicated that the yellow coat phenotype is derived from Indian indicine ancestry, whereas the black coat phenotype emerged through introgression from wild bovine lineages and artificial hybridization with Wagyu cattle. Comparative analysis of Indian indicine cattle with divergent coat colors revealed distinct LEF1 haplotypes within a shared CORIN background, suggesting an ancient and complex domestication history underlying coat color variation. These findings provide direct evidence that introgression has shaped phenotypic variation in East Asian cattle and offer novel insights into the genetic architecture of pigmentation, with implications for future breeding strategies.

Pigs have emerged as valuable large-animal models for cardiac xenotransplantation; however, the temporal dynamics of myocardial development in this species remains insufficiently defined. This study analyzed gene expression patterns across four key developmental stages (neonatal, juvenile, sexual maturity, and adulthood) to delineate the molecular mechanisms driving porcine myocardial development. Increases in heart weight were accompanied by proportional expansion of myocardial fiber area and chamber size, reflecting coordinated structural development. Transcriptomic profiling of myocardial tissue by RNA sequencing (RNA-seq) identified 2 189 differentially expressed genes (DEGs) across stage comparisons. Short time-series expression miner (STEM) analysis classified these DEGs into four major expression clusters enriched in pathways associated with myocardial development, immune responses, cell proliferation, and metabolic processes. Among 359 DEGs conserved across all developmental stages, six candidate genes were strongly associated with myocardial development. Reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) confirmed a significant correlation between the expression of these candidate genes and myocardial development in porcine tissue. These findings establish a transcriptomic framework for porcine myocardial maturation and provide a molecular basis for advancing cardiac xenotransplantation.

Cytoplasmic accumulation of TDP-43 is a pathological hallmark of amyotrophic lateral sclerosis (ALS) and other neurodegenerative diseases. While current studies have primarily focused on gene regulation mediated by full-length nuclear TDP-43, the potential effects of cytoplasmic TDP-43 fragments remain less explored. Our previous findings demonstrated that primate-specific cleavage of TDP-43 contributes to its cytoplasmic localization, prompting further investigation into its pathological effects. In the cynomolgus monkey brain, we observed that mutant or truncated TDP-43 was transported onto the ribosome organelle. Ribosome-associated transcriptomic analysis revealed dysregulation of apoptosis- and lysosome-related genes, indicating that cytoplasmic TDP-43 induces neurotoxicity by binding to ribosomes and disrupting mRNA expression. These findings provide mechanistic insights into the gain-of-function effects of pathological TDP-43.

While the functions of body coloration have been well characterized in many animal taxa, the molecular mechanisms governing its production remain poorly understood. This study investigated the genetic and biochemical basis of yellow body coloration in a mutant form of the Yongzhang golden soft-shelled turtle (YGT, Pelodiscus sinensis), which exhibit a striking yellow phenotype. Comparative pigment analysis revealed that YGTs have significantly lower melanin and higher carotenoid pigmentation compared to atrovirens wild-type turtles (AWTs), while pterin concentrations did not differ between the two groups. Functional validation experiments demonstrated that a single amino acid substitution (I481R) in tyrosinase-related protein 1 ( tyrp1) plays a pivotal role in the reduction of melanin production in YGTs. Expression of tyrp1 from YGTs and AWTs in A375 cells, in which human tyrp1 (h tyrp1) function was depleted by CRISPR-Cas9, led to a specific reduction in melanin production in cells expressing the YGT- tyrp1 variant. Moreover, bco1 and bco2, genes negatively associated with carotenoid content, showed reduced expression in YGTs, suggesting that yellow coloration is achieved through a reduction in melanin pigmentation combined with an accumulation of carotenoids. These findings elucidate the molecular basis of yellow body coloration in turtles and enhance our understanding of pigment regulation in vertebrates.

The silver-lipped pearl oyster ( Pinctada maxima) is the largest and most commercially valuable pearl-producing oyster, renowned for its ability to generate large, lustrous pearls. This species is a sequential hermaphrodite, with pearl production displaying notable sexual dimorphism. Consequently, understanding the molecular mechanisms governing sex determination and differentiation is crucial for advancing breeding strategies in the pearl oyster industry. To elucidate these mechanisms, this study conducted integrative transcriptomic analyses of P. maxima gonadal tissues using isoform sequencing (Iso-seq) and RNA sequencing (RNA-seq). Comparative analysis of ovarian and testicular tissues identified 2 768 differentially expressed genes (DEGs). Gene co-expression network analysis delineated four key modules, including three sex-specific modules and one shared module. Key genes implicated in sex determination and maintenance were identified, including FOXL2, NANOS1, and β-catenin, important for ovarian maintenance, and DMRT, SOX30, FEM1, and FOXJ1, crucial for testicular maintenance. These genes, widely studied in other taxa, were confirmed as hub genes in the sex-related modules of P. maxima. Interestingly, genes within the shared module were significantly enriched in the spliceosome pathway. Alternative splicing analysis highlighted its extensive role in gonadal tissues, with more pronounced activity observed in the testis compared to the ovary. Nearly half (47.83%, 375) of the identified genes undergoing differential alternative splicing (DASGs) also exhibited differential transcript usage (DTUGs), while only 17% of DTUGs overlapped with DEGs. Genes associated with sex differentiation, such as DMRT, β-catenin, and U2AF2, displayed sex-specific and/or sex-biased isoforms. These findings offer novel insights into the molecular basis of sex differentiation in P. maxima, which could inform the development of targeted breeding strategies aimed at sex control, thereby enhancing pearl quality and yield in aquaculture. This study offers a robust molecular foundation for advancing breeding programs and optimizing production in the pearl oyster industry.

Automated behavior monitoring of macaques offers transformative potential for advancing biomedical research and animal welfare. However, reliably identifying individual macaques in group environments remains a significant challenge. This study introduces ACE-YOLOX, a lightweight facial recognition model tailored for captive macaques. ACE-YOLOX incorporates Efficient Channel Attention (ECA), Complete Intersection over Union loss (CIoU), and Adaptive Spatial Feature Fusion (ASFF) into the YOLOX framework, enhancing prediction accuracy while reducing computational complexity. These integrated approaches enable effective multiscale feature extraction. Using a dataset comprising 179 400 labeled facial images from 1 196 macaques, ACE-YOLOX surpassed the performance of classical object detection models, demonstrating superior accuracy and real-time processing capabilities. An Android application was also developed to deploy ACE-YOLOX on smartphones, enabling on-device, real-time macaque recognition. Our experimental results highlight the potential of ACE-YOLOX as a non-invasive identification tool, offering an important foundation for future studies in macaque facial expression recognition, cognitive psychology, and social behavior.

Cichlid fishes are a textbook example for adaptive radiations, since they diversified into several hundred highly specialized species in each of three great East African lakes. Even scale-eating, an extremely specialized feeding mode, evolved independently multiple times in these radiations and in Lake Tanganyika alone, six endemic scale-eating species occupy this extremely specialized ecological niche. Perissodus microlepis went a step further, by evolving bilaterally asymmetrical heads with an intra-specific polymorphism where left- and right-headed morphs predominantly scrape scales from the opposite sides of their prey. While the bilateral asymmetry of scale-eating cichlids has been known, exactly which craniofacial features explain the laterality of the heads remained unclear. Here we aimed, by utilizing micro-computed tomography (μCT), to resolve this issue of how bilateral symmetry in the skeletal structure is broken in scale-eating Perissodus. Our 3D geometric morphometrics analysis clearly separated and identified the two groups of either left- or right-headed fish. In addition, we observed consistent asymmetric volume changes in the premaxilla, maxilla, and mandible of the craniofacial structures, where left-headed fish have larger jaw elements on the right side, and vice versa. The bimodality implies that the effect sizes of environmental factors might be minor while genetics might be responsible to a larger extent for the asymmetry observed in their head morphology. High-speed video analyses of attacks by asymmetrical morphotypes revealed that they utilize their asymmetrical mouth protrusion, as well as lateralized behavior, to re-orientate the gape towards the preferred side of their prey fish to more efficiently scrape scales.

While variable regions of immunoglobulins are extensively diversified by V(D)J recombination and somatic hypermutation in vertebrates, the constant regions of immunoglobulin heavy chains also utilize certain mechanisms to produce diversity, including class switch recombination (CSR), subclass differentiation, and alternative expression of the same gene. Many species of birds, reptiles, and amphibians express a truncated isoform of immunoglobulin Y (IgY), termed IgY(ΔFc), which lacks the υCH3 and υCH4 domains. In Anseriformes, IgY(ΔFc) arises from alternative transcriptional termination sites within the same υ gene, whereas in some turtles, intact IgY and IgY(ΔFc) are encoded by distinct genes. Different from the previously reported IgY(ΔFc) variants, this study identified a truncated IgY in the snake Elaphe taeniura, characterized by the loss of only a portion of the CH4 domain. Western blotting and liquid chromatography-tandem mass spectrometry confirmed that this truncated IgY is generated by post-translational cleavage at N338 within the IgY heavy chain constant (CH) region. Furthermore, both human and snake asparaginyl endopeptidase were shown to cleave snake IgY in vitro. These findings reveal a novel mechanism for the production of shortened IgY forms, demonstrating that the immunoglobulin CH region undergoes diversification through distinct strategies across vertebrates.

While viral infections can disturb the host gut microbiome, the dynamic alterations in microbial composition following infection remain poorly characterized. This study identified SRV-8-infected monkeys and classified them into five groups based on infection progression. 16S rRNA amplicon sequencing revealed significant alterations in the relative and inferred absolute abundance of bacterial genera UCG-002, Agathobacter, Coprococcus, and Holdemanella during the early stage of SRV-8 infection, coinciding with provirus formation. These microbial shifts were accompanied by functional modifications in bacterial communities at the same stage. In contrast, ITS amplicon sequencing indicated no significant differences in fungal composition between healthy wild-type and SRV-8-infected monkeys. Spearman correlation analyses demonstrated close interactions between intestinal bacteria and fungi following SRV-8 infection. Additionally, SRV-8 seropositive groups exhibited significantly elevated mRNA expression levels of pro-inflammatory ( TNF-α, IFN-γ, IL-1β, and IL-6) and anti-inflammatory ( IL-10) cytokine genes, highlighting close associations between inflammatory cytokines and immune responses. Overall, these findings provide a comprehensive characterization of bacterial and fungal microbiota dynamics and inflammatory cytokine responses associated with SRV-8 infection, clarifying the pathobiological mechanisms underlying SRV-8 infection from the perspective of the gut microbiome.