Search Results (316)

With the rapid development of oyster farming and the emergence of new varieties, the identification and evaluation of genetic resources have become fundamental to the effective utilization of oyster germplasm resources. To evaluate the impact of selective breeding on the germplasm of Crassostrea ariakensis, this study conducted genetic structure analysis on five successive generations including four generations selected (F1 to F4) focusing on both fast growth and high glycogen content and one base population (F0) based on partial mitochondrial cox1 and rrnL gene sequences. Results showed that the 649 bp cox1 and 488 bp rrnL sequences exhibited (A+T)-biased composition and showed positive AT skew. A total of 12 haplotypes were found for the cox1 sequences, while only three haplotypes were detected for the rrnL sequences. However, among the F1 to F4 populations, only three cox1 haplotypes and two rrnL haplotypes were observed. Based on cox1 sequences, the values of the haplotype diversity index, average number of nucleotide differences, and nucleotide diversity index all decreased progressively from F1 to F4, indicating a reduction in genetic variation due to selective breeding. All populations exhibited a low level of nucleotide diversity (<0.05). In addition, the intra-population genetic distance declined from F0 to F4, with significant genetic differentiation between F0 and F1, as well as between F0 and F4 (p < 0.05). In contrast, only the F0 and F4 population had multiple rrnL haplotypes, and no statistically significant genetic differentiations were observed based on rrnL fragments (p > 0.05). The AMOVA results showed that intra-population genetic variation exceeded inter-population variation, regardless of whether it was assessed using the cox1 gene or the rrnL gene, indicating that substantial genetic diversity persists within populations despite multiple generations of selection, and complete genetic differentiation across generations has not been achieved. These findings indicate that the selectively bred lines retain considerable genetic potential and can serve as a valuable resource for future breeding programs. Full article

Vitellaria paradoxa subsp. paradoxa C.F.Gaertn., is one of the most important components of sub-Saharan agroforestry systems, providing to rural communities, especially women, with socio- economic, environmental, and nutritional benefits. Despite its importance, the species is threatened and remains semi-domesticated. To better preserve and improve this resource, the genetic diversity and structure of 88 mother trees originated from Senegal and Burkina Faso were studied by analysing 17 phenotypic traits and 3196 SNP markers. The results revealed similar level of observed heterozygosity (Ho) between the Senegalese and Burkinabe populations (Ho = 0.16), whereas the average number of alleles per population (Na) and the expected heterozygosity (He) ranged from 0.33 to 0.34 and 0.38 to 0.39, respectively, indicating moderate to low genetic diversity. Furthermore, the polymorphic information content ranged from 0.15 for Senegal to 0.25 for Burkina Faso. Both ADMIXTURE and cluster analysis delineated our collection into two groups depending on the origin. The AMOVA showed that the highest fraction of variation was within individual, indicating a very low genetic differentiation (Fst = 0.0006) between population. At the phenotypic level, the G2 cluster representing the Senegalese genepool recorded the highest performance in terms of nut and kernel attributes, cariten and unsaponifiable matters contents, while higher crude fat, Diglyceride, Triglyceride, and Triacylglycerol Mono Stearoyl Olein Stearin contents were observed in the Burkina Faso collection (G1). The present findings on the species’ genetic diversity and genetic structure constitute a good start to strengthen the species tree improvement and conservation programs. Full article

Background: Common bean (Phaseolus vulgaris L.) is an important grain legume crop of nutritional and economic value across Africa. Genetic improvements of the crop to enhance productivity and resilience depend on understanding the diversity within the African germplasm. Methods: Following PRISMA guidelines, the genetic diversity and population structure of common bean in Africa were reviewed systematically based on existing research. A protocol for conducting the systematic review was developed registered in OSF. Twenty-nine studies met the inclusion criteria after a comprehensive search in ScienceDirect, PubMed, Google Scholar, PubMed, AGRICOLA, Taylor & Francis, and SpringerLink. Data on molecular markers and diversity metrics, thus PIC, He, and AMOVA, were extracted and synthesized qualitatively. Results: Despite substantial heterogeneity in panel sizes, reporting completeness, and marker systems (SSR, SNP, POX, ISSR), consistent patterns emerged. Studies revealed moderate to high levels of genetic diversity. Population-structure analyses recovered the canonical Andean and Mesoamerican gene pools with extensive admixture and high gene flow. AMOVA results indicated that a substantial proportion of total genetic variation was attributed to within-population components. Conclusions: The results are consistent with previous studies, but the sample size and types of markers make direct comparisons impossible. More future studies should use standardized genotyping approaches to increase data consistency. These insights are useful for yield improvement under both non-stress and stress conditions and for developing Africa’s diverse environments. Full article

Rivomarginella morrisoni (Gastropoda: Marginellidae) is a narrowly distributed freshwater snail inhabiting drainage basins of central and southern Thailand. To clarify patterns of genetic differentiation across its range, 45 individuals from 11 sites across eight river basins were analyzed using two dominant molecular markers: sequence-related amplified polymorphism (SRAP) and inter-simple sequence repeats (ISSR). SRAP primers produced higher polymorphic information content (PIC) values than ISSR primers (0.35 vs. 0.27). Analysis of molecular variance (AMOVA) revealed strong population structure, with 80.29% of the genetic variation occurring among populations and 19.71% within populations Population differentiation statistic (PhiPT) = 0.803, p < 0.001). Unweighted Pair Group Method with Arithmetic mean (UPGMA) and principal coordinate analysis (PCoA) consistently separated central and southern populations, and STRUCTURE supported K = 2 as the most likely number of clusters. Similarly, principal component analysis (PCA) of morphological traits also distinguished specimens into two groups corresponding to these geographic regions, confirming region-specific divergence. Overall, the genetic and morphological patterns indicate restricted gene flow among basins and a clear separation between central and southern lineages of R. morrisoni. This study provides the first molecular evidence of population structure in this species and offers important baseline information for future taxonomic, ecological, and conservation research on freshwater marginellid snails. Full article

From the 1950s to the 1970s, approximately 80,000 kg of tea seeds were introduced from mainland China to the Xizang Autonomous Region for experimental cultivation. To assess the genetic diversity patterns of these tea accessions following more than half a century of acclimatization to plateau environments, we analyzed genetic variation, population structure, and genetic distinctiveness among fifty tea germplasm using nine phenotypic traits and 30 SSR markers. Phenotypic analysis revealed a moderately high level of genetic diversity, as indicated by the mean Shannon diversity index (H′ = 1.29). Principal component analysis (PCA) indicated that phenotypic variation was not geographically structured across the collection sites. The SSR markers exhibited a high degree of polymorphism, with an average polymorphic information content (PIC) of 0.610 and a genetic diversity index (I) of 1.437, indicating substantial genetic variation. Analysis of molecular variance (AMOVA) revealed that genetic differentiation occurred predominantly within populations, accounting for 91.49% of the total genetic variation. Similarly, 97.86% of the variation was attributed to differences within elevational gradients. Discriminant analysis of principal components (DAPC) and Bayesian population structure modeling (STRUCTURE) both identified two genetic clusters among the studied genotypes. Our results have practical implications for tea breeding programs by providing guidance for parental selection, informing germplasm collection management, and supporting the conservation of genetic resources. Full article

Understanding the genetic diversity and structure of regional cacao and its close relatives is essential for strengthening conservation strategies and enhancing the resilience of Amazonian agroforestry systems. This study evaluated the genetic diversity, population structure, and varietal relationships of 48 sexually derived regional accessions of Theobroma cacao, T. grandiflorum, and T. bicolor with desirable morpho-agronomic traits, together with eight universal T. cacao reference clones, all cultivated in farmer-managed agroforests of the northwestern Colombian Amazon, using a panel of 15 SSR markers. The loci exhibited substantial allelic richness (mean Na = 8.53) and consistently high expected heterozygosity (Hexp = 0.74), with numerous private alleles indicating species- and lineage-specific divergence. Bayesian clustering, ΔK inference, and minimum spanning networks identified four genetically coherent subpopulations corresponding to the three species and a distinct lineage within T. cacao, strongly aligned with the discriminant analysis of principal components (DAPC) results. Analysis of Molecular Variance (AMOVA) revealed that most genetic variation occurred among subpopulations (56.68%), while pairwise FST (Wright’s fixation index) values confirmed strong interspecific differentiation and significant divergence within T. cacao. No isolation-by-distance pattern was detected. These findings demonstrate that regional Theobroma germplasm maintained in smallholder agroforests constitutes a valuable reservoir of genetic diversity that complements universal reference clones. By documenting species-level divergence and lineage-specific variation, this study supports the integration of farmer-managed genetic resources into conservation planning and highlights their importance for the long-term resilience of Amazonian cacao-based agroforestry landscapes. Full article

Rumex crispus L. is a globally distributed invasive species that has naturalized in South Korea, where its use as a medicinal, edible, and ecological restoration resource continues to expand. However, its genetic background remains insufficiently understood, underscoring the need for species-specific molecular markers to enable accurate assessments of intraspecific genetic diversity and population structure. Using 19 newly developed microsatellite markers, we analyzed 120 plants from 6 populations in the riparian zone. A total of 166 alleles were detected, with a mean polymorphism information content of 0.637. Across the six populations, genetic diversity analysis showed mean observed (Ho = 0.304) and expected (He = 0.588) heterozygosity values indicative of heterozygote deficiency (inbreeding coefficient F_IS = 0.456–0.559). Genetic differentiation was low in AMOVA (10%) and F_ST (0.048–0.120) but higher in Jost’s D (0.096–0.342). STRUCTURE analysis identified two major genetic clusters (ΔK = 2), and spatial Bayesian clustering revealed six distinct genetic units (K = 6), suggesting that partial barriers to gene flow may have influenced population structure. These findings provide essential genetic insights that can support the effective control of R. crispus spread and its potential use as a valuable plant resource. Full article

Background: Rhodiola quadrifida (Pall.) Fisch. & C.A. Mey. (Crassulaceae) is a rare medicinal species in the Kazakh Altai, yet information on its population structure and genetic diversity remains limited. This study presents findings from an investigation of natural R. quadrifida populations. Methods: The morphometric characteristics, population age structure, and genetic diversity of the plants were analysed using PCR-based genome profiling. Genetic diversity within R. quadrifida populations was assessed using PCR primers for binding sites complementary to a specific region at the 3′ terminus of a particular tRNA. Results: The populations exhibited variations in morphological traits, age structures, and reproductive strategies. The IVA-1, IVA-2 and KOK populations represent the most mature stages, characterized by a dominance of vegetative reproduction and a disturbed age structure, with a predominance of senile and virgin individuals. In contrast, the LIN-1 and LIN-2 population is characterized by a balanced age structure, encompassing all ontogenetic groups, and a mixed reproductive system that includes both sexual and vegetative propagation. Genetic diversity, as measured by Shannon’s information index, ranged from 0.194 to 0.247, indicating low genetic diversity in R. quadrifida. Analysis of molecular variance (AMOVA) revealed significantly greater variation within populations (62%) than among populations (38%). Genetic diversity was higher in the LIN-1 and LIN-2 populations, which employs a mixed reproductive system (clonal and seeds), than in populations dominated by vegetative reproduction. Both LIN populations, characterized by a mixed reproductive system, exhibited higher genetic diversity than the KOK, IVA-1 and IVA-2 populations, where vegetative reproduction predominated. Conclusions: These results underscore the necessity for priority conservation measures, including monitoring population size and age structure in populations with low levels of seed reproduction and disturbed age structure. Additional measures include supporting in situ and ex situ conservation, such as clonal collection, seed banks, and tissue cultures, as well as restricting the harvesting of medicinal raw materials. Full article

Fusarium wilt causes substantial losses in many crops, and Penicillium rubens strain 212 (PO212) is a well-established biological control agent effective against several soil-borne pathogens, including the causal agents of Fusarium wilt. Before its widespread use, it is essential to assess whether applying PO212 may affect indigenous soil microbial communities. To address this, two open-field tomato trials were conducted to evaluate spatial and temporal changes in non-target soil fungal communities following the application of PO212. Fungal community profiles were monitored over one year using PCR–DGGE of fungal rDNA, and representative DGGE bands were sequenced for taxonomic confirmation. Community structure and variability were analysed using cluster analysis (UPGMA and Neighbor-Joining) and analysis of molecular variance (AMOVA) to determine the effects of treatment, sampling date, and soil depth. PO212 application did not significantly altered the composition or diversity of indigenous soil fungal communities. DGGE banding patterns and diversity indices were similar between treated and untreated soils throughout the study period. Observed community changes were driven primarily by temporal (seasonal) variation, with samples collected at 365 days clustering separately from earlier sampling dates for both treatments. AMOVA confirmed that sampling date, rather than PO212 treatment, explained most of the variance in community composition (p < 0.05). Although PO212 persisted in soil, fluctuations in other fungal populations were minor and within the range of natural seasonal variability. Overall, field application of PO212 did not disrupt indigenous soil fungal communities, supporting its environmental safety as a biocontrol agent for managing Fusarium wilt. Full article

Objectives: This study presents a comprehensive molecular investigation of Apis cerana cerana populations inhabiting the Lüliang Mountain region, aiming to evaluate their genetic diversity and population structure using polymorphic microsatellite and mitochondrial DNA (mtDNA) markers. Methods: A total of 23 microsatellite loci and three mtDNA fragments (COI–COII, COI, Cytb) were successfully amplified, of which 21 loci were polymorphic and used for subsequent genetic analyses. Measures of genetic variability, population differentiation, and molecular variance were computed to assess intra- and interpopulation diversity. Results: High levels of genetic variation were detected (mean PIC = 0.349), with observed heterozygosity (Ho = 0.827) exceeding expected heterozygosity (He = 0.608). Analysis of molecular variance (AMOVA) revealed that 95.28% of total genetic variation occurred within populations, while 4.72% was attributed to among-population differences. Mitochondrial analyses identified 20 polymorphic sites forming 19 haplotypes, with high haplotype (Hd = 0.884) and nucleotide diversity (π = 0.00157). Conclusions: These results indicate substantial gene flow and interpopulation connectivity among A. c. cerana populations in the Lüliang region. Collectively, the findings provide critical molecular evidence supporting the conservation and sustainable management of A. c. cerana genetic resources in this area. Full article

Understanding the genetic diversity and population structure of sugarcane germplasm banks is essential for generating progenies with maximum variability. In this study, 350 accessions from the EEAOC germplasm bank were genotyped using DArT-seq markers. Genetic diversity, population structure, and variability were assessed through Bayesian analysis, principal coordinate analysis (PCoA), and analysis of molecular variance (AMOVA). Additionally, different sizes of core collections were evaluated. After filtering, 74,969 high-quality SNPs were retained, and two outlier genotypes were excluded. The mean observed heterozygosity (HO) was 0.28, while the mean expected heterozygosity (HE) was 0.3. Polymorphic information content (PIC) values ranged from 0 to 0.38 (mean 0.22), and the mean discrimination power (Dj) was 0.28. Structure and PCoA analyses consistently revealed three genetic clusters. AMOVA indicated that most of the genetic variation was found within subpopulations, while 10.25% was attributable to differences among them (p < 0.0001), where ΦFST suggested moderate genetic differentiation. Core collection analysis showed that a subset of 35 genotypes (10%) captured nearly 96% of the total genetic diversity, while a 30% core captured over 98%. These results provide valuable information for the effective management and utilization of sugarcane genetic resources and support the design of breeding strategies to develop superior cultivars. Full article

The genetic diversity and the genetic structure of widely distributed species are meaningful to explore plant adaptation mechanisms to the environment. This study investigated the effects of climatic factors on the genetic diversity and structure of Agropyron michnoi, and modeled its large-scale potential distribution shifts. A. michnoi was studied under different temperature and precipitation gradients on grassland of Inner Mongolia and North China using rbcL and trnL-F sequences. The results showed that the genetic diversity of A. michnoi was low and significantly influenced by precipitation. AMOVA results showed that genetic variation in A. michnoi occurred mainly within the population, accounting for 70.57%. Both Mantel test and partial Mantel test support a significant IBE pattern. STRUCTURE and UPGMA analyses divided the populations into two clusters. Population 10 was closely related to one cluster. The haplotype network shows only one cluster H1, and all other haplotypes have evolved from H1, which is likely the ancestral haplotype. A. michnoi, as a widely distributed species. Originating from a primitive haplotype. Large scale precipitation caused genetic differentiation into two genetic branches. The MaxEnt model predicts that A. michnoi’s distribution has expanded since the Last Glacial Maximum and will shift to higher elevations in the future due to climate change. Full article

Sebastes thompsoni is a cold-water rockfish of commercial and ecological value off the coast of Korea, requiring conservation management. We analyzed seven microsatellite loci to assess genetic diversity, population structure, and historical effective population size (N_e) of five populations obtained from the South and East Seas of Korea in 2018. The observed heterozygosity (H_O = 0.759–0.816) was higher than previously reported, and none of the STRUCTURE, DAPC, or AMOVA analyses detected geographic differentiation among samples from the South and East coasts of Korea, indicating a single population within these coasts. There was genetic flow between the five groups, with migration rates ranging from 4.1 to 19.11. However, the current N_e of all populations is estimated to be <1000, and VarEff-based reconstructions indicate a recent, severe bottleneck following an expansion approximately 600–1200 years ago (100–200 generations ago). This suggests that genetic diversity loss may persist in the future due to long-term habitat loss, fishing pressure, and ocean current fluctuations. Therefore, S. thompsoni should be established as a single management unit covering the Korean Peninsula coast, and habitat protection, overfishing control, genetic management type resource release using various mother and broodstock, and periodic genetic monitoring should be promoted. This study provides evidence to guide efforts to secure long-term genetic resilience and sustainable management of S. thompsoni in Korean coastal waters. Full article

Coral reefs, with their high biodiversity and ecological service functions, face significant threats due to climate change, overfishing, and pollution. The South China Sea (SCS) hosts rich coral biodiversity, particularly Acropora hyacinthus, a critical species for reef restoration. However, the region’s coral reefs are increasingly degraded, highlighting the urgent need for conservation efforts. In the present study, the genetic diversity and population structure of A. hyacinthus were examined based on two types of data: double-digest restriction-site-associated DNA (ddRAD) sequencing data and mitochondrial putative control region DNA (mtCR) sequences. Coral tissue samples were collected from 74 colonies inhabiting two inshore reefs (Sanya) and three offshore reefs (Xisha islands), and 748 single nucleotide polymorphisms (SNPs) and 74 mtCR sequences were obtained and utilized for downstream analysis. The results were consistent in analyses and did not cluster into two geographical groups for the inshore and offshore sites. Phylogenetic analysis showed that individuals of A. hyacinthus inhabiting the five detected sites were likely cryptic species HyaD. Furthermore, AMOVA and pairwise F_ST estimations based on both data types revealed no differentiation among five populations and between inshore and offshore reefs, which could be due to the reproductive mode of broadcast spawning for this species. However, a prevalent low level of genetic diversity was observed when compared with nearby Taiwan regions and Japan, and the geographic history results showed that the effective population size (N_e) had been decreasing for the past 300 years. Thus, we speculated that the populations of A. hyacinthus inhabiting the SCS lack the potential to cope with future climate change adequately, and multiple conservation measures should be implemented based on considering genetic diversity. Full article

To elucidate the temporal dynamics of genetic diversity across successive breeding generations of channel catfish (Ictalurus punctatus) and enhance subsequent breeding efficiency, we systematically evaluated the genetic variation in four consecutive generations using ten highly polymorphic microsatellite loci. The number of alleles (Na), effective alleles (Ne), and Shannon’s index (I) all declined with increasing generations. The mean expected heterozygosity (He) decreased gradually from 0.822 to 0.805 but remained above 0.80, indicating that all generations maintained relatively high genetic diversity. Allele frequency analysis revealed the progressive fixation of alleles potentially linked to target traits, while some rare alleles were gradually lost. Analysis of molecular variance (AMOVA) demonstrated that 98% of the genetic variation occurred within generations, with weak differentiation among generations (Fst = 0.016). UPGMA clustering further indicated that later generations diverged from the base stock, whereas genetic distances among adjacent generations progressively narrowed, suggesting increasing convergence and stabilization of genetic structure. These findings provide both theoretical insights and practical guidance for the continuous selective breeding and germplasm conservation of channel catfish. Full article