High Levels Of Gene Flow Research Articles

Genetic Features of the Bream Abramis brama from the Lake System of the Sebezhsky National Park

For the first time, the analysis of the genetic variability of microsatellite DNA for five loci in the bream Abramis brama (L.) from lakes Sebezhskoye and Necheritsa of the Sebezhsky National Park, Sebezhsky district of the Pskov region, included in the lake system, was carried out. The results obtained demonstrate the uniformity of estimates of the genetic variability of bream in the lake system. Estimates of the allelic diversity of microsatellite loci and the expected heterozygosity of local bream groups did not differ significantly. The total genetic differentiation of bream was θ = 0.004. 95% CI (-0.01; 0.01) and was significantly insignificant. The population-genetic structure based on the studied multilocus genotypes has not been revealed by the Bayesian analysis method. The result indicate a high level of gene flow between local bream groupings and make it possible to assume the presence of a genetically unified panmixed population in the Sebezh lakes system.

Monitoring spatiotemporal patterns in the genetic diversity of a European butterfly species

Abstract The importance of genetic diversity has been recognised by the Convention on Biological Diversity but attempts at monitoring or improving the genetic diversity of populations have been minimal. Here, we investigate changes over time in the genetic diversity of a wild insect species, Maniola jurtina (Lepidoptera: Nymphalidae) and present a large‐scale investigation into contemporary spatial genetic diversity. Using microsatellite markers, we calculate multiple measures of genetic diversity and divergence for M. jurtina populations over 8 years in the UK and compare these findings with long‐term abundance trends. We also conduct a large‐scale spatial analysis into the genetic diversity and population structuring of M. jurtina across Europe. All UK populations sampled have high levels of gene flow and genetic diversity, with genetic diversity stable over time. Across Europe, we find some population structuring between populations in the UK and the European mainland, suggesting restricted geneflow between the two regions. The monitoring of a wild species' genetic diversity is an achievable aim, and one that could be carried out for many species, particularly Lepidoptera. Future approaches may aim to develop higher resolution genetic markers and cover a wider range of species. The use of abundance data offers additional insight, and we find that concurrent, dedicated genetic monitoring can provide effective tracking of biodiversity trends.

Small-scale geographic differences in multiple-driver environmental variability can modulate contrasting phenotypic plasticity despite high levels of gene flow

Climate change is altering not only the mean conditions of marine environments, but also their temporal variability and predictability. As these alterations are not uniform across seascapes, their biological effects are expected to accentuate intra-specific differences in the adaptive capacity (e.g., plasticity and evolutionary potential) of natural populations. To test this theoretical framework, we assessed the phenotypic and genetic profiles of mussel from three study sites across a multi-driver heterogeneous environmental mosaic in Chilean Patagonia. Our study reveals that temporal variability, predictability, and exposure to extreme events (low pH/low salinity), collectively, can modulate the plasticity and optimal conditions of mussels. Despite these phenotypic differences, we observed low genetic differentiation, likely resulting from significant gene flow induced by aquaculture, ultimately diminishing variation among individuals from different geographic areas. Our findings underscore how variability and predictability are essential factors shaping phenotypic diversity, even at small spatial scales. Balancing these factors could enhance species resilience and ecological success, crucial for biodiversity conservation amidst climate change.

The Migration, Diversity, and Evolution of Puccinia triticina in China.

Wheat leaf rust, caused by Puccinia triticina, is one of the most common fungal diseases of wheat in China and occurs widely in various wheat-growing regions. To clarify the epidemic, spread rules, and population structure of P. triticina among different regions, 217 isolates of P. triticina collected from Hebei, Shandong, Sichuan, and Xinjiang in China were tested by 34 Thatcher near-isogenic lines and 21 pairs of EST-SSR primers. A total of 83 races were identified, and THTT, PHTT, THTS, and PHJT were the most predominant races in the four provinces in 2009. We found enriched virulence and genetic diversity in the four P. triticina populations and a significant correlation between genetic polymorphism and geographic regions. However, no significant correlation was found between virulence phenotypes and molecular genotypes. Moreover, a notable high level of gene flow (Nm = 2.82 > 1) among four P. triticina populations was detected. The genetic relationship among Hebei, Shandong, and Sichuan populations was close, possibly due to the spread of P. triticina from Sichuan to Shandong and then to Hebei. In contrast, the Xinjiang population was relatively independent. Genetic differentiation analysis showed some level of differentiation among or within populations of P. triticina in the four provinces, and the genetic variation within populations (74.97%) was higher than across populations (25.03%). Our study provides a basis for a better understanding of the regional migration, epidemic, and population structure of P. triticina in China.

Integrating genetic assortment and molecular insights for climate-resilient breeding to unravel drought tolerance in cotton

This study addresses the challenges posed by rainfall variability, leading to water deficits during critical stages of crop growth, resulting in a drastic reduction of cotton yield. In a comprehensive evaluation, thirty cotton genotypes, including five Gossypium arboreum (wild) and twenty-five Gossypium hirsutum (cultivated), were grown under rainfed and irrigated conditions. Drought tolerance indices (DTI) were evaluated, categorizing genotypes based on their resilience. Further, in-vitro screening at the seedling stage (20 days) under PEG-induced drought identified tolerant genotypes exhibiting elevated levels of free proline (19.07±5.31 mg.g−100fr.wt.), amino acids (34.59±6.51 mg.g−100fr.wt.), soluble proteins (13.73±2.65 mg.g−1fr.wt.), and glycine betaine (10.95±3.62 mg.g−100fr.wt.), in their leaves, positively correlating (p<0.001) with relative water content (87.70±3.45 %). Molecular analysis using drought-specific simple sequence repeats (SSR) markers revealed significant genetic variability in a cotton genotypes, with lower observed and higher expected heterozygosity. F statistics exposed a higher level of gene flow corresponding to low differentiation among populations. Among the genotypes group, wild GAM-67 and cultivated Deviraj emerged as the most potent, exhibiting the higher DTI and diverse gene pools. Study exhibited higher total gene diversity in drought-tolerant wild GAM-67 (0.8501) and greater expected heterozygosity (0.626) and gene flow (0.6731) in cultivated Deviraj, underlining their robust genetic adaptability to drought conditions. The integrated approach of field evaluations, in-vitro screening, and molecular analyses explained substantial genetic diversity, with the identification of promising genotypes displaying higher drought tolerance indices, elevated levels of stress-related biochemical osmolytes, and pronounced genetic adaptability, thereby contributing to the advancement of breeding initiatives for enhanced drought resilience in cotton.

Genetic Features of the Bream Abramis brama Population from the Lake System of Sebezhsky National Park

The genetic variability of microsatellite DNA has been studied for the first time for five loci in the common bream Abramis brama (L.) from lakes Sebezhskoye and Necheritsa of the Sebezhsky National Park lake system (Pskov oblast). The results demonstrate the uniformity of estimates of the genetic variability of the bream in the lake system. Estimates of the allelic diversity of microsatellite loci and the expected heterozygosity of local bream groups do not differ significantly. The total genetic differentiation of bream is θ = 0.004, 95% CI (–0.01; 0.01), and is statistically insignificant. The Bayesian analysis of the studied multilocus genotypes has not revealed any population–genetic structure. The results indicate a high level of gene flow between local bream groupings and make it possible to assume the presence of a genetically unified panmixed population in the Sebezhsky National Park lake system.

Contrasting patterns of spatial genetic structure in endangered southern damselfly (Coenagrion mercuriale) populations facing habitat fragmentation and urbanisation

AbstractAimHuman‐induced environmental changes result in habitat loss and fragmentation, impacting wildlife population genetic structure and evolution. Urbanised and geographically peripheral areas often represent unfavourable environments, reducing connectivity among populations and causing higher population genetic differentiation and lower intra‐population genetic diversity. We examined how geographic peripherality and anthropogenic pressures affect genetic diversity and genetic differentiation in the protected southern damselfly (Coenagrion mercuriale, Odonata), which has low dispersal capabilities and specific habitat requirements and whose populations are declining.LocationWe studied two areas: one in semi‐natural habitats at the periphery of the species geographic range (northern France) and the other more central to the species' range, in an urbanised area surrounding the city of Strasbourg (Alsace, eastern France).MethodsWe genotyped 2743 individuals from 128 populations using 11 microsatellite loci. We analysed the spatial distribution of neutral genetic diversity (allelic richness, heterozygosity, levels of inbreeding and genetic relatedness), the extent of genetic differentiation and population affiliations (sPCAs) within the two areas. We also examined fine‐scale patterns of gene flow in the urbanised area of Alsace by investigating patterns of isolation by distance and estimating effective migration surfaces (EEMS) method.ResultsNorthern peripheral populations showed lower levels of genetic diversity and higher levels of genetic differentiation than central Alsacian populations. Although located in anthropised habitats, geographically central Alsacian populations showed high levels of gene flow, with dispersal events mainly occurring overland and not restricted to watercourses. However, the highly urbanised city of Strasbourg negatively impacted nearby populations by reducing levels of genetic diversity and increasing population genetic differentiation.Main ConclusionsThese results showed the need for management action by restoring breeding sites and creating migratory corridors for peripheral southern damselfly populations. However, our results also highlighted the resilience of southern damselfly in central range populations facing strong urbanisation pressures.

Invasion away from roadsides was not driven by adaptation to grassland habitats in Dittrichia graveolens (stinkwort)

Invasive plants along transportation corridors can significantly threaten ecosystems and biodiversity if they spread beyond anthropogenic environments. Rapid evolution may increase the ability of invading plant populations to establish in resident plant communities over time, posing a challenge to invasion risk assessment. We tested for adaptive differentiation in Dittrichia graveolens (stinkwort), an invasive species of ruderal habitat in California that is increasingly spreading away from roadsides into more established vegetation. We collected seeds from eight pairs of vegetated sites and their nearest (presumed progenitor) roadside population. We assessed differentiation between populations in roadside and vegetated habitat for germination behavior and for response to competition in a greenhouse experiment. We also tested for increased performance in vegetated habitat with a grassland field experiment including a neighbor removal treatment. Germination rates were slightly reduced in seeds from vegetated sites, which may indicate lower seed viability. Otherwise, plants did not show consistent differences between the two habitat types. Competition strongly reduced performance of D. graveolens in both the greenhouse and in the field, but plants originating from vegetated sites did not show enhanced competitive ability. Our findings show no evidence of adaptive differentiation between D. graveolens populations from roadside and vegetated habitats to date, suggesting that invasiveness in grasslands has not been enhanced by rapid evolution in the 40 + years since this species was introduced to California. Evolutionary constraints or potentially high levels of gene flow at this small scale may limit adaptation to novel habitats along roadsides.

The effects of grassland degradation on the genetic structure of a small mammal.

Grassland degradation is challenging the health of grassland ecosystems globally and causing biodiversity decline. Previous studies have demonstrated the impact of grassland degradation on the abundance and behavior of small mammals. Little is known about how it affects the genetic structure of gregarious mammals in the wild. This study explores the effects of grassland degradation on the genetic structure of a small burrowing mammal, plateau pika (Ochotona curzoniae). We used nine microsatellite loci to analyze the genetic diversity and genetic differentiation between colonies and genetic relatedness between individuals within the colony. We found that pikas in severely degraded grasslands had a significantly higher genetic diversity within colonies, a higher level of gene flow between colonies, and a lower genetic differentiation between colonies compared to pikas in less degraded grasslands. Individuals within colonies had a significantly lower genetic relatedness in severely degraded grasslands than in less degraded grasslands. This study has provided potential evidence of a significant impact of grassland degradation on the genetic structure of pikas, which has caused a breakdown of their kin-selected colony structure.

Evaluating the impact of historical climate and early human groups in the Araucaria Forest of eastern South America

It has been hypothesized that the Araucaria Forest in southern Brazil underwent expansions in the past, driven either by human groups or by climate fluctuations of the Holocene and Pleistocene. Fossil pollen records of the Paraná pine Araucaria angustifolia, a dominant tree in that forest, provide some insights into when those may have occurred. Still, the timing of those expansions has never been estimated. To infer past range shifts and shed light on their main drivers, we employed next‐generation DNA sequencing (ddRADseq), machine learning, and a comprehensive database of fossil pollen records into a study of historical demographic inference and paleo‐distribution modeling of the Paraná pine. We found that A. angustifolia comprises two populations expanding at different times: one in the Mantiqueira mountain chain, the other in the southern Brazilian plateau. The southern population began to expand during the Last Glacial Period ~ 70 kya, long before human arrival in South America. Still, genetic analyses support that humans later impacted this population, resulting in lower genetic diversity, higher inbreeding, and high levels of gene flow over large distances with a weak pattern of isolation‐by‐distance. It is possible this resulted from human influence on seed dispersal and germination on the southern Brazilian plateau. The Mantiqueira population, in contrast, expanded only recently (~ 3 kya). This timing coincides with Holocene climatic changes and human settlements established further south, although, to date, there is little archeological evidence of human impact in the Mantiqueira. In addition, multitemporal species distribution models built from a combination of present‐day and pollen records infer a range expansion of the Araucaria Forest during glacial times until the cold humid HS1 event (~ 16 kya), when the forest was most widespread, with no evidence of glacial refugia. The combination of genomic and spatial analyses suggests that both human and climatic controls played a role in the dynamics of the Araucaria Forest.

Pan-azole- and multi-fungicide-resistant Aspergillus fumigatus is widespread in the United States.

Aspergillus fumigatus is an important global fungal pathogen of humans. Azole drugs are among the most effective treatments for A. fumigatus infection. Azoles are also widely used in agriculture as fungicides against fungal pathogens of crops. Azole-resistant A. fumigatus has been increasing in Europe and Asia for two decades where clinical resistance is thought to be driven by agricultural use of azole fungicides. The most prevalent mechanisms of azole resistance in A. fumigatus are tandem repeats (TR) in the cyp51A promoter coupled with mutations in the coding region which result in resistance to multiple azole drugs (pan-azole resistance). Azole-resistant A. fumigatus has been isolated from patients in the United States (U.S.), but little is known about its environmental distribution. To better understand the distribution of azole-resistant A. fumigatus in the U.S., we collected isolates from agricultural sites in eight states and tested 202 isolates for sensitivity to azoles. We found azole-resistant A. fumigatus in agricultural environments in seven states showing that it is widespread in the U.S. We sequenced environmental isolates representing the range of U.S. sample sites and compared them with publicly available environmental worldwide isolates in phylogenetic, principal component, and ADMIXTURE analyses. We found worldwide isolates fell into three clades, and TR-based pan-azole resistance was largely in a single clade that was strongly associated with resistance to multiple agricultural fungicides. We also found high levels of gene flow indicating recombination between clades highlighting the potential for azole-resistance to continue spreading in the U.S.IMPORTANCEAspergillus fumigatus is a fungal pathogen of humans that causes over 250,000 invasive infections each year. It is found in soils, plant debris, and compost. Azoles are the first line of defense antifungal drugs against A. fumigatus. Azoles are also used as agricultural fungicides to combat other fungi that attack plants. Azole-resistant A. fumigatus has been a problem in Europe and Asia for 20 years and has recently been reported in patients in the United States (U.S.). Until this study, we did not know much about azole-resistant A. fumigatus in agricultural settings in the U.S. In this study, we isolated azole-resistant A. fumigatus from multiple states and compared it to isolates from around the world. We show that A. fumigatus which is resistant to azoles and to other strictly agricultural fungicides is widespread in the U.S.

Genetic diversity and differentiation analysis reveals geographical structure characteristics of Dermatophagoides farinae (Acari: Pyroglyphidae).

Dermatophagoides farinae (Acari: Pyroglyphidae) has been reported as one of the major sources of indoor allergens that trigger allergic disease in humans. In this study, the genetic diversity and differentiation of nine geographic populations of D. farinae were investigated by analyzing mitochondrial and nuclear genes (COI, Cytb, COI+Cytb, and ITS). The results showed high genetic diversity across the D. farinae populations. The BX (Benxi) population showed the lowest genetic diversity, possibly due to climatic causes. Significant genetic differentiation was observed among D. farinae populations based on mitochondrial genes. The analysis of molecular variance (AMOVA) results elucidated that the contribution to the rate of variation was primarily from among populations. Phylogenetic analysis and haplotype network based on mitochondrial genes both indicated significant geographic structure among D. farinae populations. The nine geographic populations of D. farinae were divided into two groups with the Qinling Mountains-Huai River Line serving as the boundary for spatial analysis of molecular variance analysis (SAMOVA). However, the Mantel test analysis showed no association between genetic differentiation and geographic distance because of the high level of gene flow among some populations through the transportation of stored food. Overall, these results indicate both significant genetic differentiation among D. farinae populations, but also significant gene exchange between them. Results from the analysis of the nuclear gene ITS differed from the mitochondrial genes due to differences in molecular markers between mitochondrial genes and nuclear genes. These observations improve our understanding of the genetic diversity and structure of D. farinae populations.

Aromatic rice (Oryza sativa L.) landraces of Indo‐Gangetic Plains of India harbor rich genetic diversity

AbstractAromatic rice (Oryza sativa L.) germplasm conserved in global genebanks needs intensive characterization to assess genetic diversity and population structure for crop improvement. We analyzed a panel of 92 accessions of non‐Basmati aromatic rice landrace germplasm with 23 phenotypic traits and 48 microsatellite markers. The landrace accessions displayed a huge phenotypic diversity for traits, namely, culm length, flag‐leaf length, panicle‐bearing tillers (PBT), plant height, panicle length, peduncle length, panicle exsertion, grain length, grain width, hull color, and 1000‐grain weight (TGW). Phenotypic clustering revealed three major clusters and five principal components explained 81.24% of the variance. TGW was associated positively with grain length, grain width, peduncle length, and grain yield but negatively with culm length and PBT. A total of 528 microsatellite alleles were detected, with 11.0 alleles per locus, revealing the presence of high polymorphism. Genetically, four subpopulations were detected based on structure analysis. In the germplasm, high levels of gene flow (Nm = 1.51) and gene diversity (HE = 0.83) were found. Among the subpopulations, we discovered high levels of inbreeding (FIS = 0.92) and moderate genetic differentiation (FST = 0.14). High polymorphism information content (0.806) along with a high level of molecular variance among genotypes (79%) was detected. A large number of multiple alleles were detected in numerous landrace accessions, revealing the presence of heterogeneity and heterozygotes in the landrace germplasm. The results of the present study are vital for the utilization of landrace diversity in the genetic improvement programs designed for rice quality improvement and consumer preference.

Genetic connectivity is maintained in two insect pollinators across a human‐altered landscape

Abstract Population genetics is a valuable tool for assessing the impact of human‐altered landscapes on genetic connectivity in various species. However, when applied to insects, challenges arise due to potentially large effective population sizes (), high dispersal capacities and the recency of anthropogenic impacts. This study assessed the population genetic structure of two pollinators across a human‐altered landscape in Luxembourg. Samples from the ashy mining bee (Andrena cineraria, N = 201) and the greater bee fly (Bombylius major, N = 637) were genotyped at 25 microsatellite loci, including a genotyping‐by‐amplicon‐sequencing approach for A. cineraria. Despite high statistical power of &gt; 0.002 in B. major and &gt; 0.0025 in A. cineraria, no deviations from genetic homogeneity were detected. For both species, there was no evidence for isolation‐by‐distance or genetic clustering. Genetic homogeneity was most likely the result of high levels of gene flow that compensate for the effects of genetic drift. Estimates of ranged between several thousand to tens of thousands, although precision was low. Simulations highlighted that genetic lag times can substantially affect our ability to detect recent (&lt;50 generations) population differentiation when is very large. Lag times were shorter with data from 25,000 simulated di‐allelic loci, but only when sample sizes remained high. Insect genetic studies should consider lag times due to large and ensure sample size and markers offer adequate power to reject the null hypothesis of no landscape effect on genetic connectivity.

On the genetic diversity of Chimaera monstrosa Linnaeus, 1758 (Chordata, Chondrichthyes, Holocephali) in the Mediterranean Sea

The sustainable management and conservation of deep-sea species may be hampered by the paucity of data on their population structure and connectivity, in the face of ever-increasing fisheries pressure and other forms of impacts on deep-sea ecosystems. The rabbit fish, Chimaera monstrosa, is a deep-sea cartilaginous fish, reported worldwide in the past, but currently distributed only in the North-Eastern Atlantic Ocean and Mediterranean Sea. It is currently experiencing high levels of mortality associated with by-catch. Its slow growth, low fecundity and late maturity make this species particularly vulnerable to anthropogenic impact, although little is known about processes of connectivity between ecoregions. This study utilized DNA sequencing of the mitochondrial cytochrome c oxidase subunit I (COI) gene to investigate the population structure and demography of C. monstrosa both at the small (around the coasts of Sardinia, western Mediterranean Sea) and at larger spatial scales (at the pan-Mediterranean level, and between the Atlantic Ocean and the Mediterranean Sea). A total of 100 new sequences were obtained from specimens of Mediterranean origin, identifying 15 new haplotypes out of the 30 known so far for the species. Evidence of feeble but significant differentiation was detected among locations within the Tyrrhenian basin. Bayesian clustering analyses indicated the occurrence of three distinct haplogroups: the most common spread all over the Mediterranean, and the other two limited to the Western basin. Greater levels of genetic differentiation were found between the Atlantic and Mediterranean populations which constituted two main genetic clusters, with no shared haplotypes. The two populations became separated at the end of the Middle Pleistocene, with a clear sign of demographic expansion during the same period. The rabbit fish constitutes an important exception to a general paradigm of deep-sea species being connected by high levels of gene flow and such results could be useful to implement current management strategies to conserve this vulnerable by-caught species.

Cryptic sexual reproduction in an emerging Eucalyptus shoot and foliar pathogen

AbstractEucalyptus scab and shoot malformation is an emerging disease and a serious threat to the global plantation forestry industry. The disease appeared in North Sumatra (Indonesia) in the early 2010s and the causal agent was recently described as a novel species, Elsinoe necatrix. Nothing is known regarding its possible origin or why it emerged rapidly to cause a serious local epidemic. To investigate its population biology, we developed 15 polymorphic microsatellite markers as well as mating‐type markers using genome sequences for two E. necatrix isolates. Isolates of the pathogen were collected from different host varieties at four locations in the Lake Toba region of North Sumatra and characterized using these markers. A high level of genotypic diversity was observed for all populations with little to no genetic differentiation between sampling areas. Discriminant analysis of principal components, genotype networks and analysis of molecular variance all showed a lack of population structure and a high level of gene flow among sampling regions. Mating‐type ratios and linkage disequilibrium analyses suggest that sexual recombination is likely to be occurring, although a sexual state has not been found for the pathogen. The results of this study highlight the fact that new genotypes of E. necatrix, probably arising from cryptic sexual recombination, will challenge efforts to manage the disease, and that breeding and selection for tolerance will require substantial host genetic diversity.

Microsatellites reveal high levels of genetic admixture in the natural populations of Laurus azorica, Lauraceae

Laurus (Lauraceae) species are currently restricted to isolated refugia in the southern Black Sea, Mediterranean Basin, southern Morocco, and Macaronesian archipelagos. One to three species of Laurus has been recognized: the Azorean endemic Laurus azorica, L. nobilis from the Mediterranean, and L. novocanariensis from Madeira and the Canary Islands. This study aims to determine the population structure, genetic diversity, and associated patterns of gene flow within and between Azorean populations, using eight existing SSR markers. We also included plant material from L. nobilis populations found in the Azores, for comparison. Amplification was performed in 212 samples of L. azorica and in 30 samples of L. nobilis. For L. azorica, 78 alleles were amplified (average 9.75 alleles per loci). Bayesian analysis with STRUCTURE unveiled five genetic groups for the Azorean accessions, with high level of genetic admixture. Genetic diversity was generally high, with moderate levels of genetic differentiation among L. azorica populations. Moreover, high gene flow levels, likely mediated by past human translocations and naturally, by birds, might have contributed to the high level of genetic admixture observed possibly reflecting hybridization events between L. nobilis and L. azorica. Conservation measures should be applied to some populations of São Miguel, Santa Maria, and Flores Islands, based on the number of private alleles, and further, ad hoc translocation events should be avoided. Conservation in situ and the preservation of laurel forest remains are recommended. The study of this species’ taxonomy, genetics, and population dynamics in the Macaronesian region should be continued.

Conservation implications of high gene flow and lack of pronounced spatial genetic structure in elephants supported by contiguous suitable habitat in north‐western India

AbstractThe western Terai Arc Landscape (wTAL) in Uttarakhand, India, marks the range limit for the Asian elephant in north‐western India. This region has been impacted by land‐use changes and infrastructure expansion for the last seven decades. To evaluate the impact of habitat deterioration on the population structure of elephants in the region, we characterized their genetic diversity and local genetic structure using mitochondrial (D loop) and nuclear DNA (microsatellites; n = 15) markers. We used tissue samples of 114 elephants from five different sub‐populations, collected between 2005 and 2014. The genetic variation was moderate (HO = 0.49–0.55) compared with other Indian elephant populations. Two mtDNA haplotypes were identified without strong spatial patterns across wTAL. Bayesian individual‐based clustering algorithm identified two genetic clusters (K = 2) with high admixture (50% at Q &lt; 0.7) and no spatial adherence. Though K = 1 was not supported by the Bayesian algorithm, multivariate analysis and sibship patterns did not indicate genetic differentiation. The lack of spatial genetic structuring suggests high levels of gene flow, indicating that this population is still panmictic. This suggests that the life history traits of elephants as well as the ecological features of this landscape influence genetic connectivity. However, ongoing land use changes necessitate regular genetic monitoring in wTAL to identify incipient structuring caused by anthropogenic barriers to movement.

Genetic Analysis Reveals Relationships Among Populations of Puccinia striiformis f. sp. tritici from Shaanxi-Gansu-Ningxia-Xinjiang of Northwestern and Sichuan-Yunnan of Southwestern China.

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive diseases worldwide. In China, wheat stripe rust generally occurs in the northwestern and southwestern regions; however, the genetic relationships of Pst populations between these regions are largely unclear. To determine the population structure and potential migration route in these regions, 235 isolates collected from Xinjiang (XJ), Gansu (GS), Ningxia (NX), Shaanxi (SX), Sichuan (SC), and Yunnan (YN) provinces in 2021 and 2022 were phenotyped using two sets of Pst differentials and genotyped using 20 competitive allele-specific PCR-single nucleotide polymorphism (KASP-SNP) markers. The phenotype tests indicated that CYR34, CYR32, and CYR33 were the predominant races with different occurrence frequencies in different regions and years. Genotypic analysis revealed that a total of 183 multilocus genotypes were identified, and the genetic diversity in the YN subpopulation was the highest. The genetic background in the SX subpopulation was similar to that in the GS and NX subpopulations, and the genetic background in the YN subpopulation was similar to that in the SC and SX subpopulations. A high level of gene flow (Nm) was found between the SX and GS, SX and NX, GS and NX, and SC and YN subpopulations, suggesting the migration of Pst among these regions, while a small amount of Nm existed between the SX and SC subpopulations. SC may serve as a bridge connecting Pst subpopulations between the northwestern provinces (SX, GS, and NX) and the southwestern provinces (SC and YN). With a relatively high genetic distance and low Nm values compared with other Pst subpopulations, XJ is considered a relatively independent epidemiological region in China. These results improved our current understanding of the wheat stripe rust epidemic in northwestern and southwestern regions of China.

Local adaptation with gene flow in a highly dispersive shark.

Adaptive divergence in response to environmental clines are expected to be common in species occupying heterogeneous environments. Despite numerous advances in techniques appropriate for non-model species, gene-environment association studies in elasmobranchs are still scarce. The bronze whaler or copper shark (Carcharhinus brachyurus) is a large coastal shark with a wide distribution and one of the most exploited elasmobranchs in southern Africa. Here, we assessed the distribution of neutral and adaptive genomic diversity in C. brachyurus across a highly heterogeneous environment in southern Africa based on genome-wide SNPs obtained through a restriction site-associated DNA method (3RAD). A combination of differentiation-based genome-scan (outflank) and genotype-environment analyses (redundancy analysis, latent factor mixed models) identified a total of 234 differentiation-based outlier and candidate SNPs associated with bioclimatic variables. Analysis of 26,299 putatively neutral SNPs revealed moderate and evenly distributed levels of genomic diversity across sites from the east coast of South Africa to Angola. Multivariate and clustering analyses demonstrated a high degree of gene flow with no significant population structuring among or within ocean basins. In contrast, the putatively adaptive SNPs demonstrated the presence of two clusters and deep divergence between Angola and all other individuals from Namibia and South Africa. These results provide evidence for adaptive divergence in response to a heterogeneous seascape in a large, mobile shark despite high levels of gene flow. These results are expected to inform management strategies and policy at the national and regional level for conservation of C. brachyurus populations.