Search Results (154)

Leptospirosis is a globally distributed zoonosis of major public health and veterinary relevance, caused by pathogenic species of the genus Leptospira. Brazil is a hotspot for transmission due to its ecological diversity and complex host–environment interfaces. This study explored the genetic diversity and structure of circulating pathogenic Leptospira spp. in Brazil through a single-locus sequence typing (SLST) analysis based on the secY gene. A total of 531 sequences were retrieved from GenBank and subjected to phylogenetic and haplotype diversity analyses. Maximum likelihood reconstruction revealed strongly supported clades for seven species, with L. interrogans being the most prevalent and broadly distributed across hosts and regions. This species showed evidence of clonal expansion, with a dominant haplotype (n = 242) shared by humans, domestic animals, and wildlife. In contrast, L. santarosai and L. noguchii exhibited high haplotypic diversity and reticulated network structures, reflecting greater evolutionary variability. The species L. kirschneri and L. borgpetersenii displayed reduced haplotypic variation, the latter mainly associated with cattle, consistent with its host-adapted profile. Host- and biome-based haplotype networks revealed both the broad ecological adaptability of certain lineages and the exclusive presence of haplotypes restricted to specific environments, such as those found in marine mammals from the Atlantic Ocean. Genetic distance analyses confirmed the strong taxonomic resolution of the gene secY, which effectively distinguished closely related species while capturing intraspecific diversity. These findings provide a comprehensive molecular overview of pathogenic Leptospira in Brazil, highlighting ecological connectivity across hosts and biomes, as well as the contrasting evolutionary dynamics among species. Beyond describing genetic patterns, our analyses emphasize evolutionary processes, host–environment connectivity, and the implications for One Health. This integrative framework strengthens the basis for surveillance and control strategies in other endemic regions in the world. Full article

Distant hybridization is key to trait innovation and speciation, with Cyprinidae hybrid phylogeny helping to clarify diversification mechanisms. Yet, a major gap persists in Cyprinidae studies: the stabilization mechanisms of interspecific distant hybrid lineages. To address this, we systematically analyzed the molecular phylogeny of seven Cyprinidae distant hybrid lineages and their parental species, using an integrative genetic framework encompassing four mitochondrial genes (Cytb, COI, 16S rRNA, D-loop) and five nuclear genes (EGR2b, IRBP2, RAG1, RAG2, RH2). Homologous sequences of 41 representative Cyprinidae species (85 samples) were retrieved from GenBank to supplement the dataset. Phylogenies were reconstructed from concatenated sequences, complemented by haplotype networks. Intra-/interspecific divergence was quantified using two mitochondrial genes (COI, Cytb) and two nuclear (RAG1, RH2). The results showed that these hybrid lineages exhibited variation patterns analogous to other Cyprinidae species. Both ML and BI trees reconstructed exhibited congruent topologies with high support (bootstrap/BPP > 80%), resolving genus/species-level relationships. While most hybrids clustered intermediately between their parental species, they typically displayed maternal affinity. A notable exception was the 2nNCRC (a homodiploid hybrid from Cyprinus carpio ♀ × Megalobrama amblycephala ♂), which displayed convergent evolution toward Carassius auratus. COI-based K2P genetic distance analysis revealed 2nNCRC had a much closer relationship with C. auratus (0.0119) than with its parents (0.1249 to C. carpio, 0.1552 to M. amblycephala). These nine genes elucidate the genetic relationships between Cyprinid hybrid lineages and progenitors, serving as pivotal molecular markers for parentage tracing and genetic dissection of distant hybridization mechanisms. The integrated mitochondrial–nuclear marker system in this study advances understanding of cytonuclear coadaptation and the stabilization of interspecific distant hybrid lineages in Cyprinidae. Specifically, it provides a precise tool for parentage tracing, Cyprinid germplasm conservation, and targeted regulation of hybrid breeding—laying a foundation for exploring hybrid speciation and developing elite aquaculture germplasms. Full article

The Pheophorbide a oxygenase (PaO) is a key enzyme in chlorophyll degradation and plays an important role in plant senescence. However, the PaO gene’s function in sorghum remains underexplored. In this study, we identified five SbPaO gene family members in the sorghum genome through bioinformatics analysis. Analyses of gene structure, phylogeny, and collinearity revealed high conservation of this gene family among grass crops, suggesting similar functions. Subcellular localization and protein network predictions indicated that SbPaOs may participate in chlorophyll catabolism and regulate leaf senescence. Expression pattern analysis showed that SbPaO1, SbPaO3, SbPaO4, and SbPaO5 were highly expressed in leaves and significantly upregulated during senescence. Haplotype analysis found three SbPaO genes significantly linked to thousand-grain weight (TGW); superior haplotypes SbPaO1-hap4, SbPaO3-hap5, and SbPaO4-hap4 notably increased this trait. Single-gene improvements increased TGW by 10.57–17.20%, dual-gene aggregation by 18.78–24.75%, and three-gene aggregation by 29.09%. The study also developed Kompetitive Allele-Specific PCR (KASP) markers that identify superior haplotypes with 100% accuracy. In summary, this study’s results provide a theoretical basis and genetic resources for further exploration of haplotype pyramiding strategies to breed new high-yielding sorghum varieties and delineate a clear research direction for subsequent functional validation and breeding practices. Full article

Geographic isolation can shape genetic variation and structure, leading to divergence between island and mainland populations. The Oriental Garden lizard (Calotes versicolor Daudin, 1802) is a widespread agamid reptile in Asia, occurring across diverse habitats from continental Southeast Asia to offshore islands. We examined mitochondrial cytochrome c oxidase subunit I (CO1) sequence variation in 143 individuals from 23 localities across the Andaman Sea and Gulf of Thailand to assess genetic diversity and structure between insular and mainland populations. Forty-six haplotypes (Cve1–Cve46) were identified, with haplotype diversity (Hd) ranging from 0.500 to 1.000 and nucleotide diversity (π) from 0.0057 to 0.0265. AMOVA revealed low to moderate differentiation between island and mainland groups in the Andaman Sea (F_CT = 0.075, p > 0.05) and negligible differentiation in the Gulf of Thailand (F_CT = 0.009, p > 0.05). Haplotype networks and PCoA showed clustering of most island and mainland populations within regions, with some localized divergence. Divergence-time analysis indicated that lineages split within the last 0.5 million years ago (Ma), coinciding with late Pleistocene climatic oscillations and sea-level changes. Species delimitation analyses supported three major lineages, including a geographically restricted clade confined to Trat Province and Phuket Island. These results suggest that C. versicolor populations are structured more by regional geography than strict island–mainland separation, reflecting historical connectivity and contemporary gene flow. The findings contribute to understanding reptile biogeography in Southeast Asia and highlight populations of conservation value. Full article

The tokay gecko (Gekko gecko) is a widely distributed lizard species in Southeast Asia, with significant importance in traditional medicine and the pet trade. Previous studies using mitochondrial DNA sequences revealed extensive genetic variation across its range, indicating the presence of distinct evolutionary lineages. In this study, we assessed the nuclear genetic variation and phylogenetic pattern of G. gecko using the recombination activating gene 1 (RAG1). We analyzed 105 RAG1 sequences from 16 localities across Thailand, Laos, and Cambodia, along with additional sequences from GenBank. Sequence analysis revealed 20 variable sites and 20 haplotypes (TgR1–TgR20). Haplotype network and phylogenetic analyses revealed strong regional structuring and at least three distinct evolutionary lineages (A–C), supported by the species delimitation test (PTP). Both red- and black-spotted morphs were present in different clades, indicating that external coloration does not correspond to genetic differentiation at this locus. Our results support the presence of distinct evolutionary lineages in G. gecko and emphasize the importance of integrative taxonomy for accurate species delimitation. These findings have implications for conservation, sustainable management, and regulation of international trade in this commercially exploited species. Full article

Background/Objectives: In this study, we conducted molecular identification of R.microplus and explored the genetic diversity of R. microplus for the first time in Mizoram, a Northeastern Hill (NEH) state of India bordering Myanmar. Methods: To assess genetic variation and evolutionary relationships, we employed phylogenetic analyses, genetic divergence metrics, and haplotype network construction based on mitochondrial (COX1 and 16S rDNA) and nuclear (ITS-2 and 18S rDNA) markers. Additionally, multivariate Principal Coordinate Analysis (PCoA) was used to visualize genetic differentiation among R. microplus populations. Results: Our analyses indicated that populations of R. microplus sensu lato from India, Bangladesh, and Pakistan form a closely related matrilineal lineage distinct from R. microplus sensu stricto, clustering within clade C of the COX1-based phylogeny. Globally, 24 COX1 haplotypes were recovered, with 1 haplotype identified in India. The Mizoram population exhibited a single 16S rDNA haplotype; however, intraspecific divergence was evident across India, with seven matrilineal haplotypes detected and nineteen globally. Further, five haplotypes were identified within R. microplus using the ITS-2 marker, while five haplotypes were observed within the Rhipicephalus genus using the 18S rDNA marker. Moreover, this study revealed the presence of Coxiella-like endosymbionts in 95% of the tick specimens analyzed. Conclusions: This study fills a critical knowledge gap by providing the first molecular documentation of tick diversity in Mizoram, a strategic region along the Indo–Myanmar border, and offers novel insights into the phylogeography and symbiotic associations of R. microplus and related tick taxa. Full article

Canine distemper virus (CDV) is a serious and often fatal disease caused by Morbillivirus canis, which affects domestic dogs and wild carnivores, with case-fatality rates reaching up to 47%. The hemagglutinin (H) protein mediates viral adsorption and shows high genetic variability, making it a valuable molecular marker. This study aimed to detect and characterize the H gene of CDV strains from 14 dogs with fatal neurological disease in the Brazilian states of Mato Grosso and Rondônia. Brain tissue was tested via RT-PCR for the nucleocapsid gene, and positive samples were amplified for the H gene. Ten complete H-gene sequences were obtained. Phylogenetic analysis revealed two distinct clusters within the South America I/Europe lineage: one related to strains from Uruguay and Argentina (with residues 530G/549Y) and another related to Brazilian strains (530S/549Y). One sequence (MT8) showed an intermediate position in the haplotype network but clustered phylogenetically with Uruguay/Argentina-related strains. Most sequences carried 530S/549Y, a pattern linked to altered SLAM receptor usage in wildlife. These findings demonstrate the co-circulation of two CDV clusters in Central–Western Brazil, their regional and international genetic connectivity, and amino acid substitutions potentially influencing host adaptation and antigenicity. Full article

Yak husbandry on the Qinghai–Tibetan Plateau relies on genetically resilient sire lines, yet the paternal ancestry of the locally prominent Jiuzhi breed has never been quantified. To resolve this gap, a 690 bp fragment of the Y chromosomal SRY gene was sequenced in 117 males spanning Jiuzhi (n = 12) and five neighboring Qinghai breeds and compared with three single individual public records that represent Qinghai Plateau, Tianzhu White, and Wild yaks. Alignment, haplotype calling, diversity indices, F_ST differentiation, AMOVA, multidimensional scaling, and TCS network analysis were performed. Thirty-two haplotypes were recovered; Jiuzhi yaks possessed twelve, and six of them had private alleles. Mean A + T content was 53.8%. Haplotype diversity was highest in Qinghai Plateau, Tianzhu White and Wild yaks and lowest in Larima yaks, while Jiuzhi diversity resembled that of Huanhu. Pairwise F_ST values indicated negligible differentiation between Jiuzhi and either Qinghai Plateau or Yushu yaks (F_ST ≈ 0) but pronounced divergence from Tianzhu White and Wild yaks (F_ST ≈ 0.97–0.99). AMOVA attributed 90.7% of molecular variance to among-breed differences, and multidimensional scaling clustered Jiuzhi with Jinchuan, Yushu and Huanhu. Network topology resolved two patrilineal clades, confirming dual paternal origins for Jiuzhi yaks. These data provide the first quantitative baseline for sire selection and conservation of Jiuzhi yaks and highlight close affinities with adjacent plateau breeds. Limitations include the use of single individual public sequences for Qinghai Plateau, Tianzhu White and Wild yaks (employed solely as phylogenetic anchors) and reliance on a single Y-linked locus; broader sampling and multilocus approaches will refine within-breed estimates. Full article

In this study, we assessed the genetic diversity of the Asian spongy moth, Lymantria dispar asiatica Vnukovskii (Lepidoptera: Erebidae), in Korea. We obtained 123 sequences of the species, including those from 26 regions in Korea. We analyzed the genetic diversity within the Korean samples (n = 87) and haplotype networks between the Korean and global samples (123 sequences from 26 regions in Korea and five other countries) using median-joining (MJ) network analysis. The results showed low nucleotide diversity and high haplotype diversity (π = 0.00159; Hd = 0.660). The neutrality tests were also significantly negative. The MJ network recovered a star-shaped network with diverse populations in Korea, with 12 haplotypes and a dominating haplotype, H07, in all regions. Two haplogroups, Middle and Southern, were identified. The Middle haplogroup included haplotypes from Shandong, China, indicating shared populations between the two regions. In contrast, the Southern haplogroup, primarily found in ship and harbor samples, likely originated from invasive populations. This pattern reflects the influence of human activities such as international trade, highlighting the importance of strict monitoring at ports to prevent the introduction of invasive pests and to support effective forest pest management. Full article

Equid herpesvirus 5 (EHV-5) comprises a group of heterogeneous viruses with a worldwide distribution. Primary infection typically occurs early in life, which is followed by latency and periodic recrudescence of the virus. The aim of this study was to determine the genetic variation of EHV-5 in individual animals over time and to determine the dynamics of EHV-5 spread among selected mare–foal pairs at three horse studs. The partial glycoprotein B (gB) gene was amplified from archival nasal swab samples. Sequences from 3–5 clones from each PCR product were compared using identity matrix, phylogeny, and median-joining haplotype networks. Overall, 328 clones were sequenced from long PCR products amplified from 84 EHV-5 PCR-positive swabs. The sequences were heterogeneous (89.4% to 100% nucleotide identity). The EHV-5 sequences from mares and their foals most often clustered separately, although similar EHV-5 sequences from the same mare–foal pair were also recovered. For some animals, the EHV-5 sequences from multiple sampling times clustered together, while sequences from other animals were distributed throughout the networks. Clones from the same PCR product were most often similar to each other, but divergent clones from the same PCR product were also apparent. In conclusion, the foals were likely to acquire EHV-5 infection from sources other than their dams, but some exchange of EHV-5 between mares and their foals also occurred. Some foals likely acquired EHV-5 from a single source, while others from multiple sources. These data contribute to our understanding of EHV-5 variability and the dynamics of infection in individual horses. Full article

Basic and applied research reveals the importance of sea slugs as a source of new bioactive molecules or of still little-known intra/intercellular processes, mainly linked to the highly specialised defensive strategies typical of this group of shell-less molluscs. In this context, the nudibranch Doris verrucosa (Gastropoda, Mollusca), commonly known as ‘warty dorid’, is particularly interesting due to its ability to produce de novo biochemical compounds with pharmacological properties and being the type species of the genus Doris, one of the oldest and richest in species, currently characterised by a troubled systematics. Despite its wide distribution across the Eastern Atlantic Ocean and the Mediterranean Sea, this species has not yet been characterised from a genetic point of view. Considering the importance of assessing species identity to correctly investigate the systematics and to properly unravel potentially useful applications, results from a molecular assessment of such interesting species are provided. Genetic analysis involved species delimitation, phylogeny and haplotype network methods carried out on specimens of D. verrucosa collected from highly anthropised areas of Southern Italy (central Mediterranean Sea). Furthermore, in situ observations allowed us to fill some gaps in knowledge on the ecology and the morphological variability of this species that could be useful for future comparisons. Full article

Spilostethus pandurus is a phytophagous insect widely distributed across Asia, Europe, and Africa, yet its genetic variation remains poorly understood. This study presents the first comprehensive analysis of the genetic diversity and structure of S. pandurus in Thailand using mitochondrial cytochrome c oxidase subunit 1 (CO1) sequences from 202 individuals across 27 localities. A total of 58 haplotypes were identified, with high haplotype and nucleotide diversity observed, suggesting substantial genetic variation. The haplotype network revealed a star-like topology, indicating recent population expansion or ongoing gene flow. Neutrality tests and mismatch distribution analyses showed no strong signal of recent demographic expansion. Phylogenetic analysis confirmed that all Thai specimens clustered within a well-supported S. pandurus clade along with sequences from India, Namibia, and Europe. Analysis of Molecular Variance (AMOVA) revealed significant genetic differentiation among four continental groups, indicating that geographic isolation and restricted gene flow have shaped genetic divergence at a broad biogeographic scale. Further research using highly polymorphic nuclear markers is recommended to better resolve the population structure and evolutionary history of S. pandurus in Thailand and beyond. Full article

The Triatoma rubrovaria subcomplex, comprising several triatomine species, plays a significant role in the transmission of Chagas disease in southern Brazil. Despite morphological distinctions among these species, their genetic differentiation remains poorly understood, particularly in sympatric regions. This study investigates the genetic diversity and phylogenetic relationships through DNA sequencing analysis of five sympatric species within the T. rubrovaria subcomplex (T. rubrovaria, T. carcavalloi, T. klugi, T. circummaculata, and T. pintodiasi), using a 542-bp fragment of the mitochondrial cytochrome b (mtCytb) gene. A total of 84 specimens were collected from six municipalities in Rio Grande do Sul, Brazil, and analyzed alongside laboratory-reared specimens and sequences from the GenBank. Bayesian phylogenetic reconstructions, haplotype networks, and population structure analyses revealed a lack of clear genetic differentiation among the five species, with overlapping intra- and interspecific divergences and shared haplotypes. These findings suggest either a single species exhibiting phenotypic plasticity or a group of incipient species with ongoing gene flow. This study highlights the need for a taxonomic revision and suggests that this group could serve as a valuable model for further genomic research to elucidate potential aspects of phenotypic plasticity and/or sympatric speciation in triatomines. Full article

Soil salinization is a major constraint to global crop productivity, highlighting the need to identify salt tolerance genes and their molecular mechanisms. Here, we integrated mRNA and miRNA profile analyses to investigate the molecular basis of salt tolerance of an elite Brassica napus cultivar S268. Time-course RNA-seq analysis revealed dynamic transcriptional reprogramming under 215 mM NaCl stress, with 212 core genes significantly enriched in organic acid degradation and glyoxylate/dicarboxylate metabolism pathways. Combined with weighted gene co-expression network analysis (WGCNA) and RT-qPCR validation, five candidate genes (WRKY6, WRKY70, NHX1, AVP1, and NAC072) were identified as the regulators of salt tolerance in rapeseed. Haplotype analysis based on association mapping showed that NAC072, ABI5, and NHX1 exhibited two major haplotypes that were significantly associated with salt tolerance variation under salt stress in rapeseed. Integrated miRNA-mRNA analysis and RT-qPCR identified three regulatory miRNA-mRNA pairs (bna-miR160a/BnaA03.BAG1, novel-miR-126/BnaA08.TPS9, and novel-miR-70/BnaA07.AHA1) that might be involved in S268 salt tolerance. These results provide novel insights into the post-transcriptional regulation of salt tolerance in B. napus, offering potential targets for genetic improvement. Full article

Leeches hold significant medical and pharmaceutical value for antithrombotic treatments, yet their genetic diversity patterns remain poorly understood. We performed population genetic analyses on seven Hirudinaria manillensis populations from southern China using mitochondrial protein-coding genes (MitPCGs). Complete sequences of all 13 MitPCGs were obtained from 74 individuals. Haplotype diversity exhibited a logarithmic relationship with the gene length (R² = 0.858, p < 0.001), while nucleotide diversity showed a near-perfect alternating low-high pattern (Z = 2.938, p = 0.003). Concatenated sequence analyses indicated high haplotype diversity (>0.5) and low nucleotide diversity (<0.005) across all populations, suggesting a historical bottleneck followed by rapid expansion and mutation accumulation. The haplotype network, haplotype phylogenetics, and genetic structure analyses revealed moderate genetic differentiation across populations, dividing them into three clades: a basal Yunnan population (YNHH), sub-basal Guangxi populations (GXGG, GXLZ, and GXYL), and distal Guangdong/Hainan populations (GDMM, GDZJ, and HNDA). Analysis of historical population demography revealed five phases from ancient to recent times (P1–5): growth, prolonged stability, rapid decline, rapid growth, and secondary decline. These phases correlate strongly with past climatic events, demonstrating that glacial–interglacial cycles profoundly impacted the leech’s effective population size. This study provides a key scientific basis for H. manillensis resource conservation and utilization. Full article