Search Results (923)

Artificial gynogenesis is an essential technique for aquaculture breeding. Fertile offspring of the WuLi carp (Cyprinus carpio var. Quanzhounensis, 2n = 100, WLC) were successfully produced via gynogenesis using ultraviolet-irradiated sperm from the blunt snout bream (Megalobrama amblycephala, 2n = 48, BSB). As anticipated, gonadal section examination confirmed that all gynogenetic WuLi carp (2n = 100, GWB) were female. To investigate whether paternal DNA fragments from BSB were integrated into the GWB genome, comparative analyses of morphological traits, DNA content, chromosomal numbers, 5S rDNA sequences, microsatellite DNA markers, fluorescence in situ hybridization (FISH), growth performance and nutritional composition were systematically conducted between GWB and maternal WLC. The results revealed pronounced maternal inheritance patterns across morphological characteristics, DNA quantification, chromosomal configurations, 5S rDNA sequences and FISH signals, while microsatellite detection unequivocally confirmed paternal BSB DNA fragment integration into the GWB genome. Remarkably, GWB demonstrated significantly superior growth performance and elevated unsaturated fatty acid content relative to the maternal line. This approach not only addressed germplasm degradation in WLC but also provided valuable theoretical foundations for breeding programs in this commercially significant species. Full article

Background: The relationship between genetic diversity and fitness is well understood, but few studies have investigated how behavior influences genetic diversity, or vice versa. We investigated the relationship between feeding behavior (on a pelleted diet) and genetic diversity in pikeperch, a piscivorous species. Methods: A total of 135 juvenile pikeperch from the same stock were grouped into three behavioral groups: pellet consuming, pellet refusing, and cannibalistic. Eighteen microsatellite markers were used to characterize the genetic diversity and structure of individuals. Results: The juveniles were classified into two genetic clusters: one dominated by pellet-consuming individuals and the other by pellet-refusing individuals containing equal proportions of cannibal individuals. Three of the microsatellite markers were under selection, but only one showed significant genetic segregation between the groups. For this marker, the pellet consumption was associated with low fragment length. Individual multilocus heterozygosity was significantly higher in the pellet-refusing group. Conclusions: These results suggest that pellet consumption acts as an uncontrolled selective force during domestication, influencing the genetic variability of domesticated populations. The ability to habituate to pellets has a significant genetic basis. Cannibalism does not affect genetic variability, and the emergence of the trait is independent of the propensity to consume pellets. Full article

This study investigates the genetic diversity and population structure of Castanopsis tribuloides, a vital tree species in Asian forest ecosystems. Understanding the genetic patterns of keystone forest species provides critical insights into forest resilience and ecosystem function and informs conservation strategies. We analyzed population samples collected from three distinct locations within Doi Suthep Mountain in northern Thailand using Short Tandem Repeat (STR) markers to assess both intra- and inter-population genetic relationships. DNA was extracted from leaf samples and analyzed using a panel of polymorphic microsatellite loci specifically optimized for Castanopsis species. Statistical analyses included the assessment of forensic parameters (number of alleles, observed and expected heterozygosity, gene diversity, polymorphic information content), population differentiation metrics (G_ST), inbreeding coefficients (F_IS), and gene flow estimates (N_m). We further examined population history through bottleneck analysis using three models (IAM, SMM, and TPM) and visualized genetic relationships through principal coordinate analysis and cluster analysis. Our results revealed significant patterns of genetic structuring across the sampled populations, with genetic distance metrics showing statistically significant differentiation between certain population pairs. The PCA and cluster analyses confirmed distinct population groupings that correspond to geographic distribution patterns. These findings provide the first comprehensive assessment of C. tribuloides population genetics in this region, establishing baseline data for monitoring genetic diversity and informing conservation strategies. This research contributes to our understanding of how landscape features and ecological factors shape genetic diversity patterns in essential forest tree species, with implications for managing forest genetic resources in the face of environmental change. Full article

Host genetic variability is relevant to understanding how parasites modulate natural selection in wild fish populations. Coastal lagoons are transitional ecosystems where knowledge lacks on relationships between genotypic diversity with parasitism. The aim of this study was to assess the effect of genetic diversity on host health and parasitological traits in fish inhabiting a Mediterranean lagoon. Black-striped pipefish Syngnathus abaster were collected in August 2023 and 2024 from the Mar Menor (Iberian lagoon, SE Spain). Genetic diversity was measured as Internal Relatedness (IR: a homozygosity index from microsatellite markers). Population frequency was lower for the medium IR level. For this same category, both health indices (external body condition and internal organs) indicated a worse status. Parasite prevalence, abundance and an index of life-cycle complexity (heteroxenous species) were greater for the medium level of genetic diversity. Such results are explained under a scenario of parasite-mediated disruptive selection: a higher disease pressure against the phenotypically intermediate individuals. Two contrasting strategies were detected to better control parasitism at the host genotypic level: (1) high homozygosity, and (2) high heterozygosity, which probably reflects better immuno-competence as a phenotypic trait. From an evolutionary perspective, parasites play a crucial role in shaping genetic diversity within host populations. Full article

In recent decades, fishery stock enhancement has been increasingly utilized as a restoration tool to mitigate population declines and enhance the resilience of marine fisheries. Nevertheless, persistent enhancement efforts risk eroding the evolutionary potential of wild populations via genetic homogenization and maladaptive gene flow. Using long-term monitoring data (2017–2023), we quantified the effects of large-scale Penaeus penicillatus stock enhancement (~10⁸ juveniles/yr) on wild population dynamics and genetic integrity in the Beibu Gulf ecosystem. Temporal genetic changes were assessed using eight highly polymorphic microsatellite loci, comparing founder (2017) and enhanced (2024) populations to quantify stocking impacts. Insignificantly lower expected heterozygosity was observed in the stocked population (He = 0.60, 2024) relative to natural populations (He = 0.62–0.66; p > 0.1), indicating genetic dilution effects from enhancement activities. No significant erosion of genetic diversity was detected post-enhancement, suggesting current stocking practices maintain short-term population genetic integrity. Despite conserved heterozygosity, pairwise Fst analysis detected significant genetic shifts between temporal cohorts (pre-enhancement—2017 vs. post-enhancement—2024; Fst = 0.25, p < 0.05), demonstrating stocking-induced population restructuring. Genetic connectivity analysis revealed that while the enhanced Beihai population (A-BH) maintained predominant self-recruitment (>90%), it experienced substantial stocking-derived gene flow (17% SW → A-BH). The post-stocking period showed both reduced genetic exchange with adjacent populations and increased asymmetric dispersal from A-BH (e.g., 5% to YJ), indicating that hatchery releases simultaneously enhanced population isolation while altering regional genetic structure. Our findings revealed the paradoxical dual effects of stock enhancement and allelic diversity while disrupting natural genetic architecture. This underscores the need for evolutionary-impact assessments in marine resource management. Full article

Two germplasm collections, comprising 1026 peach accessions located in Italy, were analyzed with 12 simple sequence repeat (SSR) markers. SSR reactions were performed using the multiplex-ready PCR protocol, and 147 alleles were amplified with an average of 12 alleles per locus. BPPCT001 was the most informative marker displaying the highest discrimination power (0.734). The observed heterozygosity showed an average of 0.45 alleles per locus, lower than expected (0.61). The fixation index (F) values were positive in all loci, with an average of 0.27 alleles per locus, suggesting the presence of endogamy. The DNA fingerprinting data allowed the discrimination of 80.95% of the analyzed accessions. If we exclude known sport mutations, known synonymies, and cultivars with the same pedigree, 161 accessions are mislabeled, with an error rate of 16.56% within or between collections. Population structure analysis revealed three subpopulations: modern peach cultivars, modern nectarine cultivars, and a third group mainly comprising traditional peach cultivars. The results obtained in this work will be useful to efficiently manage Genebank, reducing unwanted redundancy, synonyms and homonyms, mislabeling, and spelling errors, as well as identifying parents in controlled crosses. Full article

The walnut (Juglans regia L.) holds a significant position among Kazakhstan’s nut crops, both in terms of cultivation and consumption. Although genetic resources of walnut are accessible within the country, they remain underexplored, yet they represent a valuable foundation for breeding initiatives and the development of locally adapted varieties. Currently, a comprehensive genetic profile of these resources is lacking, which hampers their effective utilization. The aim of this research was to evaluate the genetic diversity within a collection of walnut accessions collected from the southern and southeastern regions of Kazakhstan, including Almaty and Turkestan regions. To achieve this, eight SSR molecular markers were employed, providing insights into the genetic structure and relationships among the germplasm. All markers exhibited a high degree of polymorphism, with the WGA276 locus standing out as the most informative, displaying the greatest number of alleles and a high Shannon diversity index. The average expected heterozygosity (He) was 0.704 and was significantly higher than the observed heterozygosity (Ho = 0.547), which was confirmed by t-test (t = −6.426, p < 0.05). The findings indicated substantial genetic variation and intra-population polymorphism: on average, 5.875 alleles per locus were identified, and the Shannon index was 1.444. The population from Turkestan region (population 1, Sairam-Ugam) demonstrated the highest levels of diversity. Analyses of genetic structure, conducted through STRUCTURE, PCoA, and UPGMA methods, confirmed the existence of two genetically distinct groups exhibiting considerable diversity. Future research should focus on conserving the highly diverse populations in the Turkestan region to facilitate the development of stress-tolerant varieties. These findings highlight the importance of conserving and harnessing the genetic resources of Kazakhstan’s J. regia populations for future breeding efforts. Full article

Hearing impairments (HIs) are clinically and genetically very heterogeneous. Finding the causative mutations in patients is frequently a challenge. We investigated two brothers affected by a sensorineural, moderate non-syndromic HI. Exome sequencing revealed that they carried the heterozygous c.812C>T (p.Ser271Leu) variant in GATA3. This gene encodes a transcription factor involved in embryonic development, its mutations causing the autosomal dominant HDR (hypoparathyroidism, deafness, and renal disease) syndrome. The variant affects a conserved residue within the proximal zinc-finger motif of GATA3. Sanger sequencing confirmed the presence of the variant in the two brothers, but it showed that surprisingly it was not carried by any of the parents. Segregation studies on 20 fully informative microsatellite markers in the family confirmed that the variant arose de novo. A benign SNP in the mother, close to the position of the variant, allowed us to determine that this was inherited from the father. Gene reporter functional assays supported the pathogenicity of the variant. Clinical reassessment of the two brothers did not disclose any additional abnormality. We conclude that mosaicism for this de novo mutation in the father’s germ line explains the pattern of inheritance in this family and that p.Ser271Leu is causing this unexpected phenotype of non-syndromic HI. Full article

Background/Objectives: Prostate cancer (PCa) is one of the most common cancers in men worldwide. While standard treatments often provide good initial results, many patients eventually develop resistance and experience a more aggressive relapse. Microsatellite instability (MSI) involves variations in the lengths of microsatellite base repeats in cells. Assessing the frequency of MSI is essential, as it may identify candidates for immune checkpoint inhibitors, which have shown promising outcomes. This study focuses on evaluating the MSI frequency in Mexican PCa patients and exploring its potential relationship with tumor aggressiveness. Methods: In this study, 116 formalin-fixed paraffin-embedded tumoral tissue biopsies from Mexican patients with PCa were collected from Hospital Civil de Culiacán and Pathology and Nephropathology, Diagnosis and Research Center, in the period from 2021 to 2024. The Gleason score was assessed, and the MSI was performed by multiplex PCR with a panel of five markers (NR-27, NR-21, NR-24, BAT-25, and BAT-26). High microsatellite instability (MSI-H) was defined as two or more unstable markers, low microsatellite instability (MSI-L) as an unstable marker, and microsatellite stability (MSS) as no unstable marker. Results: We found 19.83% (23/116) MSI PCa patients, of which 21.74% (5/23) were MSI-H, and 78.26% (18/23) were MSI-L. We found a major distribution of MSI-positive cases (50% (11/22)) in Gleason score 9 patients, corresponding to prognostic group 5. In addition, we found most of the instability in the BAT-26 marker in MSI PCa patients (60.87% (14/23)). Conclusions: This study is the first to evaluate the frequency of MSI in PCa within the Mexican population. Among the Mexican patients with MSI-positive PCa, there was a predominant Gleason score 9 and a majority instability of the BAT-26 marker. Full article

Camels have been essential to human survival and development across the arid Central Asian steppes, particularly in Kazakhstan, where the breeding of one-humped and two-humped camels is a longstanding tradition supporting the nomadic lifestyle. This study aimed to assess the genetic diversity and population structure of these camels across their distribution range in Kazakhstan. Blood samples from 100 individuals were collected from five locations, Almaty (ALA), Atyrau (ATR), Shymkent (SHK), Kyzylorda (KZL), and Taraz (TRZ), and genotyped using 17 microsatellite markers. All loci were polymorphic, with a mean observed heterozygosity of 0.707 in C. dromedarius and 0.643 in C. bactrianus. The highest expected heterozygosity (He = 0.939) was observed at VOLP67 in C. bactrianus and at VOLP03 in C. dromedarius. Genetic differentiation was low (FST = 0.021), indicating a weak population structure between the two species with substantial gene flow (Nm = 19.972). The hybrid analysis identified 31% hybrids, including F1, F2, and backcrosses, with the highest frequencies in KZL and TRZ, moderate frequencies in ATR, and lowest frequencies in SHK and ALA. These patterns, consistent with STRUCTURE clustering, reflect widespread but regionally variable hybridization. The phylogenetic analysis revealed three clades, separating Bactrian camels (ALA), dromedaries (SHK), and a hybrid group (ATR, KZL, and TRZ). These findings enhance our understanding of the genetic diversity of Kazakhstan’s camels and support effective conservation, breeding strategies, and genotyping applications in camel husbandry. Full article

The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis; YFP) is the only freshwater cetacean species that remains in the Yangtze River, China. Poyang Lake is connected to the main stream of the Yangtze River, and the number of YFPs in Poyang Lake constitutes approximately half of the total species population. To implement effective conservation measures and formulate scientific genetic management strategies for the YFPs in Poyang Lake, we conducted population genetic analyses on 125 blood samples from the Poyang population and 46 tissue samples from the Anqing population, utilizing mitochondrial DNA D-loop and microsatellite loci. The genetic diversity analysis revealed two haplotypes in the Poyang population, with mitochondrial genetic diversity indices of Hd = 0.481 ± 0.020 and Pi = 0.00078 ± 0.00030. Microsatellite markers further demonstrated indices of Ho = 0.610 and He = 0.655. The genetic differentiation analysis indicated that the two populations exhibited moderate genetic differentiation (0.05 < Fst < 0.15). Upon excluding the dead samples from the Anqing population, the genetic differentiation between the two populations increased and the gene flow diminished. This indicated that certain dead samples from the Anqing population might have originated from Poyang Lake or had a background of Poyang Lake–Yangtze River migration and gene exchange. This finding was further corroborated by STRUCTURE analysis, which revealed genetic admixture between the two populations. We assessed the current genetic diversity of the Poyang population and its genetic differentiation from the Anqing population. This study provides fundamental data for formulating a conservation program for YFPs in Poyang Lake. Full article

Methods: We retrospectively and cross-sectionally reviewed the cases of 648 patients with a histological diagnosis of colon adenocarcinoma. Of these, 166 had partial molecular studies, and 42 cases were selected based on the availability of the genetic markers targeted in this study. We analyzed the frequency of mutations in these genes, as well as their correlation with microsatellite instability (MSI). Results: A high mutation rate was found in the KRAS gene (52.4%). NRAS mutations were less frequent (8.9%), whereas BRAF mutations were observed in 20.8% of cases. This allowed us to identify a patient subgroup with MSI, representing 12.1% of cases. Among the 42 patients analyzed for KRAS, NRAS, BRAF, and MSI mutations, a significant association was observed between KRAS mutations and microsatellite stability, while no association was found between NRAS mutations and MSI. BRAF mutations showed a statistically significant association with MSI (p < 0.05), with the most common mutation being c.1799T > A, p.Val600Glu. The objective of this study is to demonstrate that the NGS-based method for evaluating MSI is rigorously valid compared to the results obtained using IHC and PCR. Conclusions: Comprehensive NGS profiling from the start improves diagnostic efficiency by saving time, tissue, and costs compared to gene-by-gene analysis. It also enables better molecular characterization and facilitates tailored therapeutic strategies, particularly in identifying candidates for targeted therapy and immunotherapy. This approach supports efficient tumor classification based on using KRAS, BRAF, NTRK, ERBB2, and PIK3CA as key markers, along with MSI status. We recommend that, if initial NGS is not feasible, start with KRAS analysis, then test BRAF and MSI if no mutation is found. Full article

In the era of precision oncology, comprehensive molecular profiling is critical for guiding targeted and immunotherapy strategies. This study presents the analytical and clinical validation of a 1021-gene next-generation sequencing (NGS) panel, designed for use with both formalin-fixed paraffin-embedded (FFPE) tissue- and liquid-biopsy specimens. Analytical validation confirmed the assay’s high sensitivity and specificity across variant types—including SNVs (Single Nucleotide Variations), indels, CNVs (Copy Number Variations), and fusions—down to a 0.5% variant allele frequency. The assay also accurately identified microsatellite instability (MSI) and tumor mutational burden (TMB), essential biomarkers for immunotherapy. Clinical validation was performed on over 1300 solid tumor samples from diverse histologies, revealing actionable alterations in over 50% of cases. The panel detected on-label treatment biomarkers in 12.57% of patients, increasing to 20.15% when immunotherapy markers were included. Additionally, the assay demonstrated strong concordance with orthogonal methods and was effective in detecting variants in plasma-derived circulating tumor DNA in 70% of evaluable cases. These findings support the robust performance and broad clinical applicability of the 1021-gene panel for comprehensive genomic profiling in both tissue and liquid biopsies, offering a valuable tool for personalized cancer treatment. Full article

Himantoglossum metlesicsianum is a threatened orchid with low population numbers and fragmented distribution, present in four of the Canary Islands. This study focused on assessing the genetic variability and population genetic structure of the natural populations known to date, identifying those characteristics of the species that condition the flow and genetic variation. For that purpose, we collected samples from eight sites in its distribution range and developed 14 polymorphic microsatellite markers. Despite its rarity, this orchid presents high levels of genetic diversity and a homogeneous population structure, characterised by a low degree of genetic differentiation and patterns consistent with high genetic connectivity among populations. Our results suggest that the species might show dichotomy in seed dispersal, combining long- and short-distance events. In addition, it is possible that pollen cross-pollination (pollinia) between adjacent sites may also be involved. In conclusion, these findings reveal unexpectedly high genetic diversity and connectivity among populations, despite the species’ rarity and fragmented distribution, highlighting key biological traits that should be considered in future conservation and recovery plans. Full article

The Lutjanidae family includes multiple species highly important to the global fishing industry. In Brazil, approximately 40% of the fishing landings come from a species of this family, the dog snapper, Lutjanus jocu, among the most abundant in the northeast-region fisheries. This study aimed to analyze the genetic diversity and population structure of this species in the states of Bahia and Espírito Santo through the use of microsatellite markers. The dog snapper presented a high genetic variability in the studied populations, with the presence of a distinct population stock in northern Bahia probably driven by habitat suitability, larvae retention, and fishing pressure. The L. jocu sampling sites exhibited an excess of heterozygosity, a low allelic richness, and M-ratio values close to critical levels, probably indicating a recent population decline. Additionally, the low inbreeding indices and high genetic diversity values suggest a significant connectivity and considerably effective population sizes. Although these characteristics may reflect population stability, anthropogenic factors such as habitat loss, fragmentation, and overfishing may pose threats to the sustainability of the species, particularly along the northeastern coast of Brazil. Full article