Genetic Structure Research Articles

Analysis of the genetic diversity and population structure of Tilia amurensis from China using SSR markers: Implications for conservation

Tilia amurensis is a deciduous broad-leaved tree in the Malvaceae family. It is one of the second-class key protected wild plants in China. The evaluation of genetic polymorphisms of crucial protected species is necessary for conserving germplasm resources. In this study, 15 pairs of highly polymorphic SSR primers were used to analyse the genetic diversity of eight T. amurensis populations and the population structure of nine Tilia populations distributed in China. At the population level (Na = 6.050, Ne = 2.930, I = 1.123, HO = 0.485, HE = 0.523), there was a high level of genetic diversity. The AMOVA results showed that 12 % and 88 % of the total variation occurred among and within populations, respectively. The degree of genetic differentiation was moderate (FST = 0.124), and the level of gene flow was high (Nm = 1.763). The results of UPGMA cluster analysis, PCoA and structure analysis (ΔK = 2) revealed different degrees of gene introgression between the eight T. amurensis populations and Tilia japonica as the outgroup. These findings have important implications for formulating appropriate conservation strategies.

Application of iPBS-retrotransposons markers for the assessment of genetic diversity and population structure among sugar beet (Beta vulgaris) germplasm from different regions of the world

Application of iPBS-retrotransposons markers for the assessment of genetic diversity and population structure among sugar beet (Beta vulgaris) germplasm from different regions of the world

Genetic Diversity of Bluefish Population in Türkiye Coastal

Bluefish (Pomatomus saltatrix) is a commercially important, highly migratory predatory fish species distributed along the coasts of Türkiye. Conservation and sustainability of bluefish populations requires knowledge of the genetic structure of the population, but There are no genetic studies on bluefish in Türkiye. In this study, the population structure of Bluefish in the coastal regions of Türkiye was investigated by sequence analysis of mitochondrial DNA gene regions (Cytochrome b and Displacement-loop) and nuclear gene region (Rhodopsin). We tried to identify bluefish samples collected from 14 regions in the coastal region of Türkiye by analyzing two mtDNA gene sequences (Cyt b and D-loop) and nuclear gene region (Rhodopsin). While a total of 35 haplotypes were found in the Cytb gene region, a total of 132 haplotypes were found in the D-loop (control region) gene region. A single haplotype was detected in all stations for Rhodopsin. Also, the maximum likelihood trees based on Cyt b and D-loop sequences suggested relationship of Bluefish populations from Türkiye and the world. Results showed a low level of genetic differentiation between Bluefish populations in the study area, but Aegean and Mediterranean populations are more diverse than other populations due to migratory trait of this species.

Population structure of longtail tuna (Thunnus tonggol) within and across Indonesia’s fisheries management areas (FMAs) and neighboring countries based on mitochondrial control region

Longtail tuna (Thunnus tonggol), one of the neritic tuna species commonly found in the coastal areas of the Indo-Pacific region, is known to be in an overfishing state in certain areas, including in Indonesia. Understanding the condition of the T. tonggol population within Indonesia is very important in managing its fisheries policy. This research aims to understand the population genetic structure of T. tonggol across Indonesia's Fisheries Management Areas (FMAs), as well as to investigate the phylogeography of T. tonggol within the Indo-Pacific region. A total of 586 samples were collected from 18 locations within Indonesia’s six FMAs, and two locations from Malaysian waters. A 520 bp portion of mtDNA control region was amplified and sequenced. Data analysis was conducted using 586 total sequences generated from this study, and 336 sequences retrieved from GenBank, as well as provided by the author of previous study. Population structure analysis indicated a panmictic population of T. tonggol within six Indonesian FMAs and within the neighboring countries (Malaysia, Andaman Sea, Vietnam, Philippines, and India), with an indication of population expansion. These data do, however, reveal two potentially distinctive clades, one showing an affinity among samples from certain parts of Indonesia (East Aceh, West Aceh, Medan - FMA571 & FMA572) and India. Based on this finding, the T. tonggol fisheries should be managed as a single management unit both within Indonesia’s FMA and within neighboring countries, while also emphasizing localized genetic diversity to protect the sustainability of the species and its fishery.

Purposive breeding strategies drive genetic differentiation in Thai fighting cock breeds.

Fighting cock breeds have considerable historical and cultural place in Thailand. Breeds such as Lueng Hang Khao (LHK) and Pradu Hang Dam (PDH) are known for their impressive plumage and unique meat quality, suggesting selection for fighting and other purposes. However, information regarding the genetic diversity and clustering in indigenous and local Thai chickens used for cockfighting is unclear. To investigates the genetic diversity and differentiation in Thai fighting cock breeds, including populations for cockfighting, ornamental aspects, and consumption. Thai fighting cook breeds, including LHK and PDH chickens were analyzed using genotyping with 28 microsatellite loci. Data were compared to a gene pool library from "The Siam Chicken Bioresource Project" to understand the impact of human selection on genetic differentiation. Fighting cock strains from different breeds may cluster owing to shared breeding goals. The analysis of several chicken breeds showed subpopulation differentiation driven by artificial selection and genetic drift, affecting the genetic landscape and causing genetic hitchhiking. Eleven of 28 microsatellite loci showed hitchhiking selection, indicating directional selection in fighting cocks. Additionally, analyses revealed admixture with domestic chicken breeds and minimal influence of red junglefowl in the gene pool of Thai fighting chickens. These findings inform breed improvement, selection strategies, genetic resource management, and maintaining genetic diversity in fighting cocks. Analysis of Thai Fighting chicken breeds revealed a correlation between utilization and subpopulation differentiation. Specifically, selection for cockfighting and ornamental traits appears to explain the observed genetic structure within these breeds.

Genetic structure and climate niche differentiation among populations of Leopardus geoffroyi.

Geoffroy's cat (Leopardus geoffroyi) is a small-sized felid native to South America. Given the species' distribution covering a wide variety of habitats, and the presence of high levels of anthropization in part of its range, it is possible that genetically differentiated groups exist and that they occupy different climatic niches. We assessed patterns of contemporary genetic diversity and structure in the species across most of its range, characterizing each inferred genetic group based on ecological niche models. We genotyped 11 microsatellites for 142 samples covering most of Geoffroy's cat distribution, and investigated patterns of genetic structure and diversity, applying spatial and nonspatial Bayesian clustering methods and a spatial principal component analysis. We created ecological niche models for each genetic cluster, evaluating whether these clusters occupy different climatic spaces and display differences in the suitability of different values of the climatic variables analyzed. We identified two genetic clusters, one in the north-northeast and the other in the south-southwest of the species' distribution. These clusters showed moderate FST values between them and differences in dispersal/genetic diversity. We found isolation-by-distance patterns globally and within each cluster. We observed lower expected heterozygosity compared with other studies and a north-south gradient in allelic richness. The southern cluster showed lower genetic variability and a more restricted climatic niche suggesting that this group is more vulnerable to the effects of the current context of climate change. Individuals from the southern genetic cluster are under different pressures, likely a product of the particularly dry habitat they occupy. Climatic variables associated with habitat suitability suggest the southern cluster has affinity for the arid and semiarid conditions present in its distribution. Conservation measures should consider the genetic structure observed and differences in climatic spaces to maintain the evolutionary potential of the species.

Genetic Diversity and Population Structure of Amphidromous Goby (Stiphodon semoni) in Western Part of Southern Java Waters

Graphical Abstract Research Highlight The genetic diversity of Stiphodon semoni is high. All populations have high haplotype diversity except for Cimaja. No genetic structure is observed within the populations of semoni. The population of semoni has undergone demographic expansion. Cibareno River has the potential to be a protected area. Abstract Fishing activities negatively impact fish populations, potentially causing a decline in fish stocks. Nevertheless, ensuring diversity and connectivity among populations can mitigate these adverse effects. To evaluate the connectivity of river mouths in the western part of Southern Java waters, we sequenced forty Stiphodon semoni individuals from five populations using mitochondrial cytochrome oxidase subunit 1 as molecular markers. The study revealed that S. semoni populations showed high diversity (0.821), with the population in Cimaja displaying the lowest diversity (0.464). Furthermore, the result of the analysis of molecular variance was a Fst value of 0.0630 with a p-value of 0.22. These results along with the result of the haplotype network indicated no significant genetic differences among these populations. This implies that the river mouths in the western part of Southern Java waters are interconnected. The distribution of mismatches showed a single peak, indicating that the populations have undergone demographic expansion. This information could be valuable for the conservation and management of S. semoni in the western part of the Southern Java waters.

Go west, young bunting: recent climate change drives rapid movement of a Great Plains hybrid zone.

Describing how hybrid zones respond to anthropogenic influence can illuminate how the environment regulates both species distributions and reproductive isolation between species. In this study, we analyzed specimens collected from the Passerina cyanea x P. amoena hybrid zone between 2004 and 2007 and between 2019 and 2021 to explore changes in genetic structure over time. This comparison follows a previous study that identified a significant westward shift of the Passerina hybrid zone during the latter half of the twentieth century. A second temporal comparison of hybrid zone genetic structure presents unique potential to describe finer-scale dynamics and to identify potential mechanisms of observed changes more accurately. After concluding that the westward movement of the Passerina hybrid zone has accelerated in recent decades, we investigated potential drivers of this trend by modeling the influence of bioclimatic and landcover variables on genetic structure. We also incorporated eBird data to determine how the distributions of P. cyanea and P. amoena have responded to recent climate and landcover changes. We found that the distribution of P. cyanea in the northern Great Plains has shifted west to track a moving climatic niche, supporting anthropogenic climate change as a key mediator of introgression in this system.

Establishing the Performance of Next-Generation Amplicon Sequencing for Detection of Giardia duodenalis in Ready-to-Eat Packaged Leafy Greens

Giardia duodenalis is a globally distributed intestinal parasite that commonly infects both humans and animals. G. duodenalis is a species complex, which includes eight assemblages that vary both in genetic structure and host specificity. The prevalence of mixed-assemblage G. duodenalis cysts on food, an understudied infection route for G. duodenalis, remains unknown. In the present study, a method able to detect G. duodenalis mixed-assemblage infections using next-generation amplicon sequencing (NGS) of the beta-giardin gene was applied in combination with the US-FDA’s BAM Chapter 19b protocol for the detection of G. duodenalis from fresh produce to ascertain the limit of detection of G. duodenalis on leafy greens. Ready-to-eat baby Romaine lettuce was inoculated with 5 (n = 5), 20 (n = 10), 100 (n = 10), 200 (n = 10), or 1,000 (n = 10) G. duodenalis cysts of the assemblage B strain H3. Detection of G. duodenalis was successful in 100% of the samples seeded with 1,000, 200, and 100 cysts, in 50% of the samples seeded with 20 cysts, and in none of the samples seeded with 5 cysts. We thus demonstrate robust detection of G. duodenalis on packaged leafy greens using the BAM Chapter 19B method coupled with assemblage-sensitive NGS. This protocol provides a new diagnostic tool useful for both prevalence studies and outbreak investigations involving fresh produce that may assist in better describing the role of G. duodenalis in foodborne illness and in protecting consumers from contaminated fresh produce.

Genetic structure analysis of yak breeds and their response to adaptive evolution

Yaks are crucial genetic resources in the Tibetan Plateau and surrounding regions. Throughout the long process of domestication, natural and artificial selection pressures have enabled yaks to demonstrate adaptive characteristics to the environment in terms of physiological structure and genetic molecules, but no systematic cell analysis has been carried out on this phenomenon of yaks. Here, the population structure and genetic diversity of yak were studied by WGRS, and the genes related to yak adaptability were excavated. Combined with scRNA-seq method, the transcription map of yak lung tissue and skin tissue was constructed, which provided a new comprehensive insight into yak adaptability. The analysis of yak population structure showed that there was obvious genetic differentiation between TZ _ yak and other seven yak populations, while there was significant genetic exchange between PL _ yak and SB _ yak at high altitude. WGRS and scRNA-seq analysis revealed that the gene HIF1A related to high altitude adaptation was expressed in various cell types, while EPAS1 was predominantly expressed in epithelial and endothelial cells of yak lung tissue. Endothelial cells play a critical role in hypoxia-adapted VEGF signaling, which correlates closely with the high expression of KDR and VEGFA genes in endothelial cells and monocytes. Furthermore, in the selection signal of High _ yak vs Low _ yak, 19.8 % of the genes overlapped with the genes screened by skin scRNA-seq, including genes related to coat color such as RORA, BNC2, and KIT. Notably, BNC2 is a gene associated with melanin deposition and shows high expression levels in HS cells. Additionally, GRN in melanocytes and SORT1 in IRS play an important role in cell communication between melanocytes and IRS. These findings offer new insights into the natural polymorphism of yaks and provide a valuable reference for future research on high-altitude mammals, and potentially even human genetics.

Polar-Region Soils as Novel Reservoir of Lactic Acid Bacteria from the Genus Carnobacterium.

Polar habitats offer excellent sites to isolate unique bacterial strains due to their diverse physical, geochemical, and biological factors. We hypothesize that the unique environmental conditions of polar regions select for distinct strains of lactic acid bacteria (LAB) with novel biochemical properties. In this study, we characterized ten strains of psychrotrophic LAB isolated from hitherto poorly described sources-High Arctic and maritime Antarctic soils and soil-like materials, including ornithogenic soils, cryoconites, elephant seal colonies, and postglacial moraines. We evaluated the physiological and biochemical properties of the isolates. Based on 16S rRNA and housekeeping genes, the four LAB strains were assigned to three Carnobacterium species: C. alterfunditum, C. maltaromaticum, and C. jeotgali. The remaining strains may represent three new species of the Carnobacterium genus. All isolates were neutrophilic and halophilic psychrotrophs capable of fermenting various carbohydrates, organic acids, and alcohols. The identified metabolic properties of the isolated Carnobacterium strains suggest possible syntrophic interactions with other microorganisms in polar habitats. Some showed antimicrobial activity against food pathogens such as Listeria monocytogenes and human pathogens like Staphylococcus spp. Several isolates exhibited unique metabolic traits with potential biotechnological applications that could be more effectively exploited under less stringent technological conditions compared to thermophilic LAB strains, such as lower temperatures and reduced nutrient concentrations. Analysis of extrachromosomal genetic elements revealed 13 plasmids ranging from 4.5 to 79.5 kb in five isolates, featuring unique genetic structures and high levels of previously uncharacterized genes. This work is the first comprehensive study of the biochemical properties of both known and new Carnobacterium species and enhances our understanding of bacterial communities in harsh and highly selective polar soil ecosystems.

Genetic variation, population structure, and cluster analysis of rice (Oryza sativa L.) genotypes using morphological characteristics and molecular markers

Genetic variation, population structure, and cluster analysis of rice (Oryza sativa L.) genotypes using morphological characteristics and molecular markers

Phylogeography of a herbal Pinellia ternata reveals repeated range expansions and inter/postglacial recolonization routes on the fragmented distribution pattern in China.

Most plant phylogeographic studies in China have focused on the importance of genetic divergence and where should the shelter be located. Little attention has been paid to range expansion and recolonization routes in this region. In this study, two cpDNA fragments (psbK-psbI and trnL-F), two pairs of nuclear gene sequences (ITS and ETS), and nine pairs of SSR molecular markers were used, combined with Bayesian Skyline Plot method, gene barrier analysis, and species distribution models to explore the phylogeographical pattern, potential expansion routes and population dynamic history of Pinellia ternata from 22 population. The results showed that phylogeograhical pattern and genetic structure for P. ternata are effected by environmental heterogeneity and climate fluctuation, and it can be divided into two groups (Southwest group, Central and Eastern group) and thus there are at least two glacial refugia in China. Three expanding routes within groups were explored to contribute to the phylogeogrephic pattern of P. ternata based on the geographical distribution and network analysis of haplotypes. In a word, our study reveals repeated range expansions and inter/postglacial recolonization routes on the fragmented distribution pattern in China and resolves the refugia distributing in China and has also certain reference value for the protection of the medicinal plant P. ternata.

Genetic structure of a population of “peanutfish” (“dragonfish”) sea cucumbers using mitochondrial COI sequences in Marau, Guadalcanal, Solomon Islands

Genetic structure of a population of “peanutfish” (“dragonfish”) sea cucumbers using mitochondrial COI sequences in Marau, Guadalcanal, Solomon Islands

Revealing the Genetic Diversity and Population Structure of Garlic Resource Cultivars and Screening of Core Cultivars Based on Specific Length Amplified Fragment Sequencing (SLAF-Seq).

Garlic is an important vegetable and condiment that has good medical and health care effects. At present, the origin of Chinese garlic and its association with other types of quality are limited to the molecular marker level, and there are few reports at the genome level. Therefore, this study is based on the specific length amplified fragment sequencing (SLAF-seq) of 102 copies of garlic germplasm resources, the group structure, and further screening of the core germplasm. SLAF-seq of 102 garlic cultivars yielded 1949.85 Mb of clean data and 526,432,275 SNPs. Through principal component analysis, evolutionary tree, population structure, and genetic relationship analysis, all garlic cultivars were divided into 3 groups. Among them, Group 1 contains 45 Chinese cultivars and 1 Egyptian cultivar, which are distributed mainly in the coastal and central areas of China. Group 2 contains 36 Chinese cultivars and 1 U.S. cultivar, which are distributed mainly in Northwest China. Group 3 contains 19 Chinese cultivars, which are distributed mainly in Xinjiang, China. The genetic diversity results indicate that the fixation index (Fst) values of Group 1 and Group 2 are lower than those of Group 1 and Group 3 and that the diversity of nucleotides (π) of Group 3 is greater than those of Group 2 and Group 1. Finally, the 30 parts of the cultivars were used as the core germplasms, and there was no difference between the two cultivars in terms of core quality. In summary, this study provides tags for the determination of garlic molecular markers and genotypes and provides a theoretical basis for subsequent resource protection and utilization, genetic positioning of important agronomic traits, and molecular marking agglomeration breeding.

Novel genetic structures associated with adverse response to chemotherapy in breast cancer.

Introduction: The role of genetic variants in response to chemotherapy has been investigated in several studies. This study aimed to investigate genetic variants associated with response to chemotherapy in breast cancer (BC) patients. Methods: Significant variants (p < 5 × 10-8) associated with response to chemotherapy were obtained from GWA studies. Candidate variants were identified by haplotype analysis (r2 ≥ 0.9, D'≥0.9) using 1000Genome LD data. To determine the effects of the variants on gene expression, expression quantitative trait loci (eQTL) were evaluated. To compare the expression of the identified genes in tumor samples, expression levels were compared between TCGA tumor types and adjacent normal tissues. Results: Six rs3820706, rs147451859, rs4784750, rs17587029, rs16830728, and rs16972207 variants were significantly associated with response to chemotherapy in BC patients (p < 5 × 10-8). Seven novel haplotypic structures were identified to be associated with adverse response to chemotherapy in BC patients. These haplotypes formed two genetic structures associated with neutropenia, leukopenia, chemotherapy-induced cytotoxicity (GAG-TTAT), and chemotherapy-induced alopecia (CC-CAACTCCCGTTGCGG). These variants are located on PPCDC, NLRC5, STAM2, and TNFSF13B genes, and the expression of these genes significantly changed in BC tissues than normal tissues (P ≤ 0.05), also showing gene-gene correlation (P ≤ 0.05). Conclusions: These genetic variants and their associated novel haplotypic structures can predict adverse response to chemotherapy in BC patients and could potentially form BC-associated genetic panel for adverse response to chemotherapy.

Chromosome-level genome assembly and annotation of the Spinibarbus caldwelli

Spinibarbus caldwelli is an important freshwater economic fish in China. Owing to uncontrolled fishing, wild resources of S. caldwelli have decreased rapidly and may be on the verge of extinction. In this study, utilizing single-molecule real-time (SMRT) sequencing technology and chromatin interaction mapping (Hi-C) technologies, we assembled the first chromosome-scale genome for S. caldwelli about 1.77 Gb in size, with a contig N50 length of 11.83 Mb and scaffold N50 length of 33.91 Mb. In total 1.72 Gb (97.01%) of the contig sequences were anchored onto fifty chromosomes with the longest scaffold being 56.20 Mb. Furthermore, proximately 49.41% of the genome was composed of repetitive elements. In total, 49,377 protein-coding genes were predicted, of which 47,724 (96.65%) genes have been functionally annotated. The high-quality chromosome-level reference genome and annotation are vital for supporting basic genetic studies and will be contribute to genetic structure, functional elucidation, evolutionary inquiry, and germplasm conservation for S. caldwelli.

Genetic structure and demographic history of the dung beetle Deltochilum guildingii (Scarabaeinae): implications for conservation of the Tropical Dry Forest in the Colombian caribbean

Genetic structure and demographic history of the dung beetle Deltochilum guildingii (Scarabaeinae): implications for conservation of the Tropical Dry Forest in the Colombian caribbean

Whole Genome Sequences of Cryptotympana Atrata Fabricius, 1775 (Hemiptera: Cicadidae) in the Korean Peninsula: Insights into Population Structure with Novel Pathogenic Or Symbiotic Candidates

Background: The blackish cicada (Cryptotympana atrata) exhibits unique characteristics and is one of the model cicadas found in the Korean Peninsula. It is a species of southern origin, prefers high temperatures, and is listed as a climate-sensitive indicator species in South Korea. Therefore, this species can be utilized to study the impact of climate change on the genetic diversity and structure of populations. However, research on the genome of C. atrata is limited. Methods: We sequenced the genome of an individual collected from South Korea and constructed a draft genome. Additionally, we collected ten specimens from each of the five regions in South Korea and identified single nucleotide variants (SNVs) for population genetic analysis. The sequencing library was constructed using the MGIEasy DNA Library Prep Kit and sequenced using the MGISEQ-2000 platform with 150-bp paired-end reads. Results: The draft genome of C. atrata was approximately 5.0 Gb or 5.2 Gb, making it one of the largest genomes among insects. Population genetic analysis, which was conducted on four populations in South Korea, including both previously distributed and newly expanded regions, showed that Jeju Island, a remote southern island with the highest average temperature, formed an independent genetic group. However, there were no notable genetic differences among the inland populations selected based on varying average temperatures, indicating that the current population genetic composition on the Korean Peninsula is more reflective of biogeographic history rather than climate- induced genetic structures. Additionally, we unexpectedly observed that most individuals of C. atrata collected in a specific locality were infected with microbes not commonly found in insects, necessitating further research on the pathogens within C. atrata. Conclusion: This study introduces the draft genome of C. atrata, a climate-sensitive indicator species in South Korea. Population analysis results indicate that the current genetic structure of C. atrata is driven by biogeographic history rather than just climate. The prevalence of widespread pathogen infections raises concerns about their impact on C. atrata. Considering the scarcity of publicly available genomic resources related to the family Cicadidae, this draft genome and population data of C. atrata are expected to serve as a valuable resource for various studies utilizing cicada genomes.

Taxonomic and abundance biases affect the record of marine eukaryotic plankton communities in sediment DNA archives.

Environmental DNA (eDNA) preserved in marine sediments is increasingly being used to study past ecosystems. However, little is known about how accurately marine biodiversity is recorded in sediment eDNA archives, especially planktonic taxa. Here, we address this question by comparing eukaryotic diversity in 273 eDNA samples from three water depths and the surface sediments of 24 stations in the Nordic Seas. Analysis of 18S-V9 metabarcoding data reveals distinct eukaryotic assemblages between water and sediment eDNA. Only 40% of Amplicon Sequence Variants (ASVs) detected in water were also found in sediment eDNA. Remarkably, the ASVs shared between water and sediment accounted for 80% of total sequence reads suggesting that a large amount of plankton DNA is transported to the seafloor, predominantly from abundant phytoplankton taxa. However, not all plankton taxa were equally archived on the seafloor. The plankton DNA deposited in the sediments was dominated by diatoms and showed an underrepresentation of certain nano- and picoplankton taxa (Picozoa or Prymnesiophyceae). Our study offers the first insights into the patterns of plankton diversity recorded in sediment in relation to seasonality and spatial variability of environmental conditions in the Nordic Seas. Our results suggest that the genetic composition and structure of the plankton community vary considerably throughout the water column and differ from what accumulates in the sediment. Hence, the interpretation of sedimentary eDNA archives should take into account potential taxonomic and abundance biases when reconstructing past changes in marine biodiversity.