Search Results (447)

Replication stress (RS) is a primary driver of genomic instability in cancer, yet the contribution of transcription-coupled repair (TC-NER) to this process remains unclear. Here, we investigate how the TC-NER factor ERCC6 (CSB) shapes mutational landscapes under RS. We found that ERCC6 deficiency biases early damage signaling toward a 53BP1-mediated response, ultimately leading to senescence. Conversely, ERCC6-proficient cells prioritize survival and proliferative recovery but at the expense of distinct genomic alterations. Whole-exome sequencing reveals that ERCC6 proficiency is associated with the retention of stress-induced mutations specifically within coding regions of transcriptionally active loci, whereas ERCC6-deficient cells accumulate variants primarily in intergenic regions. These findings suggest that while ERCC6 safeguards transcriptional continuity during RS, its activity is associated with a biased retention of stress-induced mutations within coding regions in the surviving cell population. These findings reveal a previously unrecognized link between transcription-coupled repair and mutation distribution in human cells, linking TC-NER to context-dependent somatic evolution and tumor heterogeneity. Full article

The dung beetle family Geotrupidae (Scarabaeoidea) plays a vital ecological role in nutrient cycling and soil health, yet the scarcity of complete mitochondrial genome (mitogenome) data has hindered phylogenetic and comparative studies within this family. Here, we sequenced, assembled, and annotated the first complete mitogenomes of Geotrupes stercorarius and Phelotrupes auratus, collected from the Qinghai–Tibetan Plateau. Comparative analysis of these two novel mitogenomes with eight existing mitogenomes revealed conserved architectural features across Geotrupidae, such as gene arrangement, tRNA secondary structures, and small intergenic spacers. Nucleotide composition was largely conserved, though marked divergence occurred at the third codon positions. Substantial structural variation was observed in non-coding regions, particularly in the control region and the nad2-trnW spacer. Evolutionary analyses indicated strong purifying selection across all protein-coding genes, with no evidence of widespread positive selection linked to high-altitude adaptation. Phylogenetic reconstruction consistently recovered the relationships (Bolboceratinae, (Lethrinae, Geotrupinae)), with Anoplotrupes and Geotrupes forming sister genera within Geotrupinae. This study provides additional mitogenomic resources and a well-supported phylogenetic framework for Geotrupidae, resolving key taxonomic uncertainties and establishing a basis for future evolutionary and ecological research. Full article

The Yan goose (YE, Anser cygnoides) is a valuable indigenous poultry genetic resource, renowned for its superior meat quality and environmental adaptability. Despite its economic importance, the genetic basis underlying these adaptive traits remains unclear. In this study, we employed whole-genome resequencing (WGS) to perform high-throughput sequencing on a conserved population of 15 samples. Bioinformatic analyses were conducted to systematically evaluate the population’s genetic structure, and a genome-wide scan for selection signals related to economically significant traits was performed using the integrated haplotype score (iHS) method. An average of 4.43 million high-quality SNPs were identified, which were predominantly located in intergenic and intronic regions. Population structure analysis revealed a close genetic relationship within the conserved population of YE, with no significant lineage stratification observed. Pairwise sequentially Markovian coalescent (PSMC) analysis indicated that the YE underwent a severe genetic bottleneck during the Last Glacial Maximum (LGM), followed by gradual population recovery in the early Neolithic period. Genome-wide selection signal scanning identified multiple genomic regions under strong selection, annotating key genes associated with growth and development (e.g., GHRL, AKT1, and MAPK3), lipid deposition (e.g., PLPP4, SAMD8, and LPIN1), and disease resistance and stress resilience (e.g., TP53, STAT3). Functional enrichment analysis revealed significant enrichment of these genes in pathways related to glycerophospholipid metabolism (p < 0.01), purine metabolism (p < 0.01), and immune response (p < 0.01). This study not only provides a theoretical foundation for the scientific conservation of the YE germplasm resources but also offers valuable genomic resources for identifying functional genes underlying important economic traits and advancing molecular breeding strategies. Full article

Curcuminoids demonstrate diverse pharmacological activity as antioxidant, neuroprotective, antitumor, and anti-inflammatory drugs. Dimethoxycurcumin (DMC) is a metabolically stable analog of curcumin, and both drugs modify the activity of several epigenetic enzymes that affect DNA methylation and histone modifications. 5-hydroxymethylcytosine (5hmC) is an epigenetic mark involved in active demethylation and in gene expression regulation. The effect of curcuminoids on the activity and expression of TET enzymes involved in 5hmC oxidation and active demethylation in leukemia cells is unclear. In this study, we investigated the impact of curcumin and DMC on the activity and expression of the three isoforms of TET enzymes. We also studied their effect on global 5hmC and performed a genome-wide analysis of 5hmC distribution at the single CpG level using oxidative bisulfite sequencing, which can differentiate between 5hmC and 5-methylcytosine. Both curcumin and DMC increased the activity and the mRNA expression of the three isoforms of TET. Concordantly, they also increased the global 5hmC level in leukemia cells. Single CpG analysis showed that both drugs induced a 5hmC increase and active demethylation at gene promoters, CpG islands and shores, exons, introns, and intergenic regions. Curcumin induced a promoter 5hmC increase in 194 genes and promoter-active demethylation in 154 genes. On the other hand, DMC induced a promoter 5hmC increase in 173 genes and promoter-active demethylation in 171 genes. Our study identifies curcuminoids as active demethylators through the activation of TET enzymes and provides a rationale for testing their combination with DNA hypomethylating agents in leukemia animal models. Full article

Butidae is a family of teleost fishes with diverse morphological and ecological adaptations, including the marbled goby (Oxyeleotris marmorata), a large species of high economic value in Southeast and East Asia. The previous mitogenomic studies on cultured populations of O. marmorata from non-native habitats have provided limited insights into genetic divergence, structural variation, and evolutionary relationships. Hence, this study presented the complete mitochondrial genome of O. marmorata from its native habitat in Indonesia, providing structural characterization, assessment of genetic diversity, and matrilineal phylogenetic analysis. The circular mitogenome was 16,525 bp, comprising 37 genes and a non-coding control region (CR). The gene organization and strand distribution were conserved among Oxyeleotris species, with 28 genes on the heavy strand and nine on the light strand, and a pronounced A+T compositional bias. The comparative analyses of O. marmorata (from both native and cultured habitats) and Oxyeleotris lineolata mitogenomes revealed minor variations in intergenic spacers, gene overlaps, protein-coding gene (PCGs) lengths, and codon usage patterns. Conversely, the nonsynonymous and synonymous substitution ratios observed in species of the family Butidae and its closest related family (Eleotridae) indicate strong purifying selection in the present dataset. Notably, the ATG was the predominant start codon, whereas the COI gene utilized GTG, and amino acid composition analysis demonstrated high frequencies of arginine, leucine, and serine. Most transfer RNAs retained the canonical cloverleaf secondary structure except for trnS1, which lacked a functional dihydrouridine arm, whereas the CR contained four conserved sequence blocks with variable nucleotide motifs and no detectable tandem repeats. The haplotype analysis of native (Indonesia) and introduced populations (China) highlighted three haplotypes with high diversity (Hd = 1.0000) and substantial nucleotide variation (π = 0.6667). The genetic divergence across 13 PCGs was gene-specific, with COI and ND5 showing the highest variation, while ND4L and ATP8 were highly conserved. The phylogenetic analyses based on concatenated 13 PCGs using both Bayesian Inference and Maximum Likelihood methods revealed that Oxyeleotris forms a monophyletic clade and is closely related to Bostrychus sinensis. In addition, the broader phylogenetic framework inferred the matrilineal relationships within the family Butidae and its closest related family, Eleotridae. This study also recommends expanding analyses to include the mitogenomes of the remaining 17 Oxyeleotris species, together with comprehensive genomic data, to further elucidate their genetic architecture, evolutionary history, and ecological adaptability across diverse aquatic ecosystems. Full article

Transposable elements (TEs) play important roles in physiological processes, but their function in tail development remains poorly characterized. To explore their potential regulatory roles, we systematically analyzed the expression patterns of TEs during different fetal developmental stages of the sheep tail. Using RNA-seq data and the TEtranscripts pipeline, we identified differentially expressed TEs. Our key findings are as follows: (i) SINE/MIR, L1, and BovB elements exhibited significant stage-specific expression. (ii) The number of differentially expressed TEs was dynamic, with 2129 identified between stages E40–45 and E55–60, and 5554 between E55–60 and E70–75. (iii) These TEs were primarily located in intergenic regions, introns, and 3′UTRs, and their expression trends were highly consistent with those of adjacent differentially expressed genes. (iv) Pathway enrichment analysis revealed that TEs and their correlated genes between E40–45 and E55–60 were predominantly involved in tail elongation, while the comparison between E55–60 and E70–75 highlighted pathways related to tail fat formation. Furthermore, we identified specific candidate TEs associated with vertebra formation and fat deposition. This study provides novel insights into the role of TEs in shaping tail phenotypes and offers valuable information for sheep breeding programs. Full article

In this study, nine different Propionibacterium freudenreichii strains were isolated from Kars Gravyer produced by traditional methods in Turkey and identified by sequencing the 16S–23S intergenic region using species-specific primers. The isolated strains were examined in vitro for the presence of the β-galactosidase enzyme, autoaggregation ability, sensitivity against eight selected antibiotics and survivability under harsh conditions in order to determine their potential probiotic properties. After probiotic potentials were evaluated, an experimental design was made to optimize the production of vitamin B12 in a 3 L glass bioreactor P. freudenreichii NUV774. While all strains showed similar resistance (92–98%) to gastric juice (0.3% pepsin, pH 3.0), they showed resistance to intestinal fluid (0.1% pancreatin, 0.3% bile salt, pH 8.0) between 60% and 92%. It was determined that the viability after 3 and 6 h of incubation in 0.5% and 1% bile salt differed between strains. All isolates exhibited resistance to ciprofloxacin, ampicillin, and trimethoprim–sulphamethoxazole; however, most were sensitive to ofloxacin. Overall, P. freudenreichii strains showed resistance to the gastrointestinal tract, tolerance to pH 3.0, and high tolerance to bile salts. As a result of optimization, maximum vitamin B12 production was found to be 156.8 mg/L. The optimum operating conditions were calculated as temperature = 36.9 °C, aeration = 2.430 vvm, and agitation = 159.120 rpm. Hence, P. freudenreichii, as future probiotic strain candidates, will offer an alternative source to Lactobacillus, Bifidobacterium and some Bacillus spp. In addition, this study denoted that the alteration of the production of active vitamin B12 by P. freudenreichii occurs in a strain-dependent manner. Full article

Grape (Vitis vinifera spp.) accessions exhibit rich diversity, and understanding their genetic variation and evolutionary relationships is crucial for cultivar selection and utilization. A highly representative SNP marker set was developed in this study based on re-sequencing data analysis, to clarify the phylogenetic relationships among 96 grape accessions and to evaluate the genetic resolution of core markers. Using PN40024 as the reference genome, high-quality SNP loci were screened from resequencing data of the 96 accessions. A phylogenetic tree was constructed, and genetic diversity was analyzed using PCA and population structure analysis. The results showed that the 96 accessions were mainly divided into four groups: European (‘Merlot’, ‘Chardonnay’), American (‘Beta’, ‘Concord’), Euro-American hybrids (‘Vidal’, ‘Miguang’), and wild populations along with their hybrid progeny (‘Zuoyouhong’, ‘Huajia 8’). PCA and ADMIXTURE validated population differentiation, revealing clear separation between wild and cultivated accessions. Through screening of core SNP markers, 384,304 candidate SNPs suitable for probe design were identified. Further refinement yielded 2000 and 10,000 SNP markers. Detailed analysis of core marker characteristics showed that their minor allele frequency (MAF) was predominantly between 0.1 and 0.3, with the majority distributed in CDS (38.65%), intronic (30.2%), and intergenic regions. The most common mutation types were [A/G] (35%) and [C/T] (34%) transitions. The 2000 core SNPs were associated with 1220 functional genes and were significantly enriched in pathways such as protein binding, RNA transport, and plant–pathogen interaction. These findings provide an efficient tool for grape genetic diversity analysis, cultivar identification, and molecular breeding, laying the groundwork for the precise utilization of grape germplasm resources. Full article

The locust Oedaleus decorus undergoes massive outbreaks and engages in round-trip migratory flights across northern China and Mongolia. However, its specific genetic structure remains poorly understood. In this study, we sequenced the complete mitochondrial genomes of 163 O. decorus individuals from 16 locations in northern China using high-throughput sequencing data and analyzed its population structure. The results showed that these mitochondrial genomes are 15,142 to 15,914 bp in sizes, with size variation attributed to A + T-rich regions in intergenic spacers. All 13 protein-coding genes exhibited conserved lengths across samples. The overall genetic differentiation between populations was small (Fst = 0.00843), with high gene flow (Nm = 29.40). Both genetic differentiation and DAPC analyses revealed significant genetic differentiation in the New Barag Left Banner (NBL) population compared to the Zhengxiangbai Banner (ZB), Taibus Banner (TP), Xianghuang Banner (XH), and Zhenglan Banner (ZL) populations. The phylogenetic tree and haplotype network suggest Hap_20 is presumably a relatively ancestral haplotype and all haplotypes were divided into two clades, and no population formed a distinct independent clade. Our findings indicate that the O. decorus population in North China exhibits mitochondrial subtype differentiation. The lack of difference in genetic structure across different regions in North China is consistent with a high level of migratory activity by O. decorus in the region. Full article

Next-generation sequencing technology was employed to read and assemble the complete plastid genome of the ‘Mejhoul’ date palm cultivar (Phoenix dactylifera L.). The genome consisted of 158,436 base pairs (bp) with a GC content of 37.24%, and it included 95 protein-coding genes, 44 tRNA genes, and eight rRNA genes. The plastome of five ‘Mejhoul’ genotypes from Jordan was compared with three genotypes from the USA, Morocco, and the UAE. It revealed 91 single-nucleotide polymorphisms (SNPs) and 23 insertions–deletions (InDels); the majority of them (62%) were located in intergenic regions, while the remaining variants were located in intragenic regions, including tRNA and rRNA genes. When the plastomes of all eight ‘Mejhoul’ genotypes were aligned, along with major cultivars ‘Barhee’ and ‘Khalas’, 24 SNPs and 23 InDels could be found. This would enable the development of a cultivar-specific fingerprint test for authentication. The phylogenetic tree was constructed using seventeen date palm cultivars. The phylogenetic analysis places ‘Mejhoul’ as a lineage derived within Clade I rather than as an early-diverging cultivar, suggesting it shares a more recent common ancestor with ‘Deglet Noor’ and ‘Barhee’. Full article

Claviceps purpurea is a specialized phytopathogenic fungus that infects grasses and produces pharmacologically active compounds, attracting considerable interest in genomic research. In this study, we assembled and annotated the complete mitogenomes of 15 C. purpurea strains isolated from different host plants, including seven newly sequenced isolates from China. Analysis of the C. purpurea pan-mitogenome demonstrated that the accessory regions, with an average proportion of 48.23%, are the main contributor to mitogenome variation. Analysis of the 14 protein-coding genes revealed Ka/Ks ratios below 1, indicating strong purifying selection. Notably, the atp9 gene was absent in all strains, suggesting a potential adaptive gene loss. Structural variations were predominantly located in the intergenic region between rns and rnl. Phylogenetic analysis based on concatenated mitochondrial genes placed Claviceps as most closely related to the genus Epichloë. The 15 C. purpurea strains grouped into five well-supported subclades, with Chinese and non-Chinese isolates forming distinct lineages. Among these, the Chinese strains ACCC 37001 and KUNCC 11030 represented the earliest diverging lineages. This study elucidates the intraspecific variation and evolutionary patterns of the mitogenome in C. purpurea and highlights the value of mitogenome in resolving phylogenetic relationships. Full article

Grapes (Vitis spp.) are a globally significant fruit crop with a long history of cultivation and substantial cultivar diversity. Their high genetic differentiation and complex evolutionary history make them a valuable system for studying plant evolution. The chloroplast genome, known for its structural conservation and uniparental inheritance, offers a reliable molecular marker for phylogenetic reconstruction. In this study, we sequenced and assembled the complete chloroplast genomes of nine representative grape cultivars, analyzed their phylogenetic relationships, and compared structural variations. All chloroplast genomes displayed a typical quadripartite structure, with high conservation in genomic architecture, gene order and content, codon usage, and simple sequence repeats (SSRs). However, additional sequence comparisons revealed seven regions with high variation, including the genes rbcL and ndhF, and the intergenic regions rps16-trnQ, ndhC-trnV, accD-psaI, ndhF-rpl32, and trnL-ccsA. At the same time, seven natural variation sites were identified in the amino acid sequences of rbcL and ndhF. Additionally, the study’s maximum likelihood (ML) phylogenetic trees and photosynthetic index measurements suggest that developmental characteristics of grape photosynthesis may be related to the evolutionary origins of different populations. This phylogenetic classification not only elucidates the evolutionary origins of these germplasm resources but also provides a foundation for molecular-assisted breeding by identifying distinct genetic groups. Full article

Background/Objectives: The butterfish Stromateus stellatus is undervalued and usually discarded as bycatch, leading to an inefficient and unsustainable use of marine biomass. Overall, although Stromateus is the type genus of the family Stromateidae, its species are less studied than more economically important fishes. Methods: In this study, we determined and analyzed the complete mitochondrial genome sequence of S. stellatus. Furthermore, we performed maximum likelihood and Bayesian inference analyses to infer the phylogenetic relationships among 21 species of the order Scombriformes. Results: Using next-generation sequencing (NGS) and de novo assembly, a circular mitochondrial genome of 16,509 bp was obtained, exhibiting the typical vertebrate mitochondrial structure comprising 13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNA genes. Three intergenic regions were identified, including the control region and the origin of light-strand replication, along with several gene overlaps. The heavy strand nucleotide composition was determined to be 28.79% A, 27.84% C, 16.32% G, and 27.05% T, with a GC content of 44.16%. The three Peprilus and five Pampus species formed a clade together with S. stellatus, supported by high bootstrap and posterior probability values, confirming the monophyly of Stromateidae. Conclusions: The gene order and content are consistent with those reported for other Stromateidae species and correspond to the typical arrangement observed in most bony fishes. This mitochondrial genome represents the first one reported for the genus Stromateus, providing valuable insights into the genetic makeup of S. stellatus, contributing to a better understanding of marine biodiversity. Additionally, these data will support future research on pelagic fish evolution and assist in sustainable fisheries management. Full article

Background/Objectives: Legionella micdadei is a clinically significant species within the Legionella genus, requiring accurate detection methods, surveillance, and precise clinical diagnosis. Our objective was to develop a sensitive polymerase chain reaction (PCR) assay specific for L. micdadei to detect its presence in environmental specimens. Methods: We targeted the 23S–5S intergenic spacer region, which can differentiate Legionella spp. We tested the detection of L. micdadei with 20 strains and determined the limit of detection with 2 strains. We verified assay specificity with 17 strains of other Legionella spp., 62 strains of other bacterial and fungal genera, and three human DNA specimens. We evaluated intra- and inter-run precision. We tested 15 environmental specimens (water, swabs of water faucets, mulch, and soil) by PCR. Results: The PCR assay demonstrated 100% analytical specificity (no cross-reactivity with non-targeted species), 100% inclusivity (detection of all L. micdadei strains), and high precision, with a coefficient of variation ≤ 2% across replicates. The limit of detection was estimated at 5 genomic DNA copies per reaction. We detected L. micdadei in environmental specimens. Conclusions: This PCR assay enables accurate detection of L. micdadei and is not subject to competition with other Legionella spp., thereby addressing limitations of current broad-spectrum Legionella approaches. The evaluation supports its application in environmental detection for surveillance. Full article

G-quadruplexes (G4s) are guanine-rich DNA secondary structures with known regulatory roles in eukaryotes, but their functions in bacteria remain largely unexplored. Here, we systematically analyzed potential G-quadruplexes (PG4s) across 1566 bacterial genomes. PG4s showed non-random distributions, with strong enrichment in intergenic regions, particularly near gene start sites, suggesting potential roles in transcriptional regulation. Structural analysis revealed a higher proportion of short-loop G4s in these regions, indicating enhanced stability. Comparisons with randomized genomes confirmed that the observed patterns cannot be explained by GC content or genome size alone. Ecological analysis further revealed that bacteria associated with homothermic hosts exhibit significantly lower G4 densities than free-living species, suggesting reduced reliance on G4-mediated regulation in stable environments. Together, these findings highlight G4s as conserved yet context-dependent elements of bacterial genome organization and provide new insights into their potential regulatory roles in prokaryotes. Full article