scholarly journals First genome-wide analysis of an endangered lichen reveals isolation by distance and strong population structure

2017 ◽  
Author(s):  
Jessica L. Allen ◽  
Sean K. McKenzie ◽  
Robin S. Sleith ◽  
S. Elizabeth Alter
Keyword(s):  
Genetic Diversity ◽  
Population Genomics ◽  
Isolation By Distance ◽  
Geographic Distance ◽  
Distribution Models ◽  
Extrinsic Factors ◽  
Biogeographic Patterns ◽  
Ecological Requirements ◽  
Genome Wide ◽  
Isolation By Environment

AbstractLichenized fungi are evolutionarily diverse and ecologically important, but little is known about the processes driving diversification and genetic differentiation in these lineages. Though few studies have examined population genetic patterns in lichens, their geographic distributions are often assumed to be wholly shaped by ecological requirements rather than dispersal limitations. Furthermore, while their reproductive structures are observable, the lack of information about recombination mechanisms and rates can make inferences about reproductive strategies difficult. Here we investigate the population genomics ofCetradonia linearis, an endangered lichen narrowly endemic to the southern Appalachians of eastern North America, to test the relative contributions of environmental factors and geographic distance in shaping genetic structure, and to gain insights into the demography and reproductive biology of range restricted fungi. Analysis of genome-wide SNP data indicated strong evidence for both low rates of recombination and for strong isolation by distance, but did not support isolation by environment. Hindcast species distribution models and the spatial distribution of genetic diversity also suggested thatC. linearishad a larger range during the last glacial maximum, especially in the southern portion of its current extent, consistent with previous findings in other southern Appalachian taxa. These results contribute to our understanding of intrinsic and extrinsic factors shaping genetic diversity and biogeographic patterns inC. linearis, and more broadly, in rare and endangered fungi.

scholarly journals Population genomics of the Anthropocene: urbanization is negatively associated with genome-wide variation in white-footed mouse populations

2015 ◽  
Author(s):  
Jason Munshi-South ◽  
Christine P Zolnik ◽  
Stephen E Harris
Keyword(s):  
Population Genomics ◽  
Isolation By Distance ◽  
Impervious Surface ◽  
Snp Markers ◽  
Environment Modeling ◽  
Evolutionary Potential ◽  
Animal Populations ◽  
Genome Wide ◽  
Isolation By Environment ◽  
White Footed Mouse

Urbanization results in pervasive habitat fragmentation and reduces standing genetic variation through bottlenecks and drift. Loss of genome-wide variation may ultimately reduce the evolutionary potential of animal populations experiencing rapidly changing conditions. In this study, we examined genome-wide variation among 23 white-footed mouse (Peromyscus leucopus) populations sampled along an urbanization gradient in the New York City metropolitan area. Genome-wide variation was estimated as a proxy for evolutionary potential using more than 10,000 SNP markers generated by ddRAD-Seq. We found that genome-wide variation is inversely related to urbanization as measured by percent impervious surface cover, and to a lesser extent, human population density. We also report that urbanization results in enhanced genome-wide differentiation between populations in cities. There was no pattern of isolation by distance among these populations, but an isolation by resistance model based on impervious surface significantly explained patterns of genetic differentiation. Isolation by environment modeling also indicated that urban populations deviate much more strongly from global allele frequencies than suburban or rural populations. This study is the first to examine loss of genome-wide SNP variation along an urban-to-rural gradient and quantify urbanization as a driver of population genomic patterns.

scholarly journals Genetic divergence correlates with the contemporary landscape in populations of Slimy Salamander (Plethodon glutinosus) species complex across the lower Piedmont and Coastal Plain of the southeastern United States

2018 ◽  
Vol 96 (11) ◽  
pp. 1244-1254 ◽  
Author(s):  
Walter H. Smith ◽  
Jessica A. Wooten ◽  
Carlos D. Camp ◽  
Dirk J. Stevenson ◽  
John B. Jensen ◽  
...  
Keyword(s):  
South Carolina ◽  
Genetic Distance ◽  
Principal Components ◽  
Coastal Plain ◽  
Genetic Divergence ◽  
Species Complex ◽  
Isolation By Distance ◽  
Geographic Distance ◽  
Plethodon Glutinosus ◽  
Isolation By Environment

A primary goal of landscape genetics is to elucidate factors associated with genetic structure among populations. Among the important patterns identified have been isolation by distance (IBD), isolation by barrier (IBB), and isolation by environment (IBE). We tested hypotheses relating each of these possible patterns to genetic divergence in the Slimy Salamander (Plethodon glutinosus (Green, 1818)) species complex across the lower Piedmont and Coastal Plain of Georgia, USA, and adjacent areas of South Carolina, USA. We sequenced 2148 total bp, including three regions of the mitochondrial genome and a nuclear intron, and related genetic distance to GIS-derived surrogate variables representing possible IBD (geographic distance), IBE (principal components of 19 climate variables, watershed, and normalized difference vegetation index (NDVI)), and IBB (streams of fourth order and higher). Multiple matrix regression with randomization analysis indicated significant relationships between genetic distance and two principal components of climate, as well as NDVI. These results support roles for environment (IBE) in helping to drive genetic divergence in this group of salamanders. The absence of a significant influence of IBD and IBB was surprising. It is possible that the signal effects of geographic distance and barriers on genetic divergence may have been erased by more recent responses to the environment.

Geographic distribution of Rhyncholestes raphanurus Osgood, 1924 (Paucituberculata:Caenolestidae), an endemic marsupial of the Valdivian Temperate Rainforest

2011 ◽  
Vol 59 (2) ◽  
pp. 118 ◽  
Author(s):  
Gabriel M. Martin
Keyword(s):  
Potential Distribution ◽  
Species Conservation ◽  
Forest Types ◽  
Distribution Models ◽  
Biogeographic Patterns ◽  
Ecological Requirements ◽  
The Andes ◽  
Critical Areas ◽  
The Family ◽  
High Prediction

The Chilean shrew opossum (Rhyncholestes raphanurus) is the southernmost representative of the family Caenolestidae (Marsupialia : Paucituberculata). The species lives in temperate forests of southern Chile and Argentina and is currently known from <25 localities, spanning a latitudinal and longitudinal range of 2°44′ (~320 km) and 2°20′ (~190 km), respectively. Species distribution was analysed in a historical, geographic and biogeographic context, with the use of maps at different scales (region, subregion, province, ecoregion, forest types), and two potential distribution models were generated with MaxEnt. The models show a few isolated areas of high prediction values (>50%) in coastal Chile and the Andes from 39°30′ to ~42°S, and most of Chiloé Island, plus a northern and southern expansion of medium to low (<50%) prediction values. The most important environmental variables identified from the models include precipitation and some temperature-related variables. The species occurrence lies within the Andean region, Subantarctic subregion, and Valdivian biogeographic province. At a smaller scale, most of the localities occur in eight of the 22 forest types described for the Valdivian ecoregion, implying narrow ecological requirements. Identification of critical areas through potential distribution modelling may have implications for species conservation and identification of biogeographic patterns.

scholarly journals Genetic and species-level biodiversity patterns are linked by demography and ecological opportunity

2020 ◽  
Author(s):  
Chloé Schmidt ◽  
Stéphane Dray ◽  
Colin J. Garroway
Keyword(s):  
Genetic Diversity ◽  
Species Richness ◽  
Gene Diversity ◽  
Spatial Scales ◽  
Ecological Opportunity ◽  
Biogeographic Patterns ◽  
Genome Wide ◽  
Diversity Gradients ◽  
Low Levels

AbstractSpecies richness and genetic diversity are the two most fundamental products of evolution. Both are important conservation targets—species richness contributes to ecosystem functioning and human wellbeing, while genetic diversity allows those species to respond to changes in their environment and persist in the long-term. Biogeographic patterns of species richness are well-described, but we know little about patterns of genome-wide genetic diversity at similar spatial scales. Further, despite considerable attention to latitudinal trends in species richness, we still do not have a solid empirical understanding of the various processes that produce them, how they interact, or how they affect genetic diversity. Here we show that genome-wide genetic diversity and species richness share spatial structure, however, species richness hotspots tend to harbor low levels of within-species genetic variation. A single model encompassing eco-evolutionary processes related to environmental energy availability, niche availability, and proximity to humans explained 75% of variation in gene diversity and 90% of the variation in species richness. Our empirical model of both levels of biodiversity supports theory and demonstrates the importance of carrying capacity and ecological opportunity at individual and species levels for generating continent-wide genetic and species diversity gradients.

scholarly journals Landscape drivers of genomic diversity and divergence in woodland Eucalyptus

2019 ◽  
Author(s):  
Kevin Murray ◽  
Jasmine Janes ◽  
Helen Bothwell ◽  
Ashley Jones ◽  
Rose Andrew ◽  
...  
Keyword(s):  
Geographic Distance ◽  
Genomic Variation ◽  
Genomic Diversity ◽  
High Genetic Diversity ◽  
Genome Wide ◽  
Isolation By Environment ◽  
Genetic Patterns ◽  
Discrete Population ◽  
Eucalyptus Albens ◽  
Eucalyptus Sideroxylon

AbstractSpatial genetic patterns are influenced by numerous factors, and they can vary even among coexisting, closely related species due to differences in dispersal and selection. Eucalyptus (L’Héritier 1789; the “eucalypts”) are foundation tree species that provide essential habitat and modulate ecosystem services throughout Australia. Here we present a study of landscape genomic variation in two woodland eucalypt species, using whole genome sequencing of 388 individuals of Eucalyptus albens and Eucalyptus sideroxylon. We found exceptionally high genetic diversity (π ≈ 0.05) and low genome-wide, inter-specific differentiation (FST = 0.15). We found no support for strong, discrete population structure, but found substantial support for isolation by geographic distance (IBD) in both species. Using generalised dissimilarity modelling, we identified additional isolation by environment (IBE). Eucalyptus albens showed moderate IBD, and environmental variables have a small but significant amount of additional predictive power (i.e., IBE). Eucalyptus sideroxylon showed much stronger IBD, and moderate IBE. These results highlight the vast adaptive potential of these species, and set the stage for testing evolutionary hypotheses of interspecific adaptive differentiation across environments.

scholarly journals Genetic structure is stronger across human-impacted habitats than among islands in the coralPorites lobata

2019 ◽  
Author(s):  
Kaho H. Tisthammer ◽  
Zac H. Forsman ◽  
Robert J. Toonen ◽  
Robert H. Richmond
Keyword(s):  
Genetic Structure ◽  
Isolation By Distance ◽  
Geographic Distance ◽  
High Stress ◽  
Disruptive Selection ◽  
Single Location ◽  
Isolation By Environment ◽  
Genetic Patterns ◽  
Significant Genetic Structure ◽  
Contrasting Habitats

ABSTRACTWe examined genetic structure in the lobe coralPorites lobataamong pairs of highly variable and high-stress nearshore sites and adjacent less variable and less impacted offshore sites on the islands of Oʻahu and Maui, Hawai‘i. Using an analysis of molecular variance framework, we tested whether populations were more structured by geographic distance or environmental extremes. The genetic patterns we observed followed isolation by environment, where nearshore and adjacent offshore populations showed significant genetic structure at both locations (AMOVAFST= 0.04 ∼ 0.19,P< 0.001), but no significant isolation by distance between islands. In contrast, a third site with a less impacted nearshore site showed no significant structure. Strikingly, corals from the two impacted nearshore sites on different islands over 100km apart with similar environmentally stressful conditions were genetically closer (FST∼ 0, P = 0.733) than those within a single location less than 2 km apart (FST= 0.041∼0.079, P < 0.01). Our results suggest that ecological boundaries appear to play a strong role in forming genetic structure in the coastal environment, and that genetic divergence in the absence of geographical barriers to gene flow may be explained by disruptive selection across contrasting habitats.

Genetic diversity and gene flow patterns in two riverine plant species with contrasting life-history traits and distributions across a large inland floodplain

2020 ◽  
Vol 68 (5) ◽  
pp. 384
Author(s):  
William Higgisson ◽  
Dianne Gleeson ◽  
Linda Broadhurst ◽  
Fiona Dyer
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Structure ◽  
Water Resource ◽  
Isolation By Distance ◽  
Spatial Genetic Structure ◽  
Geographic Distance ◽  
Resource Development ◽  
Water Resource Development ◽  
Floodplain River

Gene flow is a key evolutionary driver of spatial genetic structure, reflecting demographic processes and dispersal mechanisms. Understanding how genetic structure is maintained across a landscape can assist in setting conservation objectives. In Australia, floodplains naturally experience highly variable flooding regimes that structure the vegetation communities. Flooding plays an important role, connecting communities on floodplains and enabling dispersal via hydrochory. Water resource development has changed the lateral-connectivity of floodplain-river systems. One possible consequence of these changes is reduced physical and subsequent genetic connections. This study aimed to identify and compare the population structure and dispersal patterns of tangled lignum (Duma florulenta) and river cooba (Acacia stenophylla) across a large inland floodplain using a landscape genetics approach. Both species are widespread throughout flood prone areas of arid and semiarid Australia. Tangled lignum occurs on floodplains while river cooba occurs along rivers. Leaves were collected from 144 tangled lignum plants across 10 sites and 84 river cooba plants across 6 sites, on the floodplain of the lower and mid Lachlan River, and the Murrumbidgee River, NSW. DNA was extracted and genotyped using DArTseq platforms (double digest RADseq). Genetic diversity was compared with floodplain-river connection frequency, and genetic distance (FST) was compared with river distance, geographic distance and floodplain-river connection frequency between sites. Genetic similarity increased with increasing floodplain-river connection frequency in tangled lignum but not in river cooba. In tangled lignum, sites that experience more frequent flooding had greater genetic diversity and were more genetically homogenous. There was also an isolation by distance effect where increasing geographic distance correlated with increasing genetic differentiation in tangled lignum, but not in river cooba. The distribution of river cooba along rivers facilitates regular dispersal of seeds via hydrochory regardless of river level, while the dispersal of seeds of tangled lignum between patches is dependent on flooding events. The genetic impact of water resource development may be greater for species which occur on floodplains compared with species along river channels.

scholarly journals Population Genomic Analysis of Two Endemic Schizothoracins Reveals Their Genetic Differences and Underlying Selection Associated with Altitude and Temperature

Animals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 447
Author(s):  
Tianyan Yang ◽  
Wei Meng ◽  
Baocheng Guo
Keyword(s):  
Mixed Model ◽  
Isolation By Distance ◽  
Genomic Analysis ◽  
Principal Component ◽  
Mantel Test ◽  
Tibet Plateau ◽  
Tarim River ◽  
Genome Wide ◽  
Isolation By Environment ◽  
Kaidu River

Schizothoracins are a group of cyprinid fishes distributed throughout the Qinghai–Tibet Plateau, which can be classified in three grades: primitive, specialised and highly specialised according to adaptation ability to plateau environments. As the only specialised schizothoracins in Xinjiang, China, Diptychus maculates and Gymnodiptychus dybowskii are ideal materials for adaptive evolution research. Based on single-nucleotide polymorphism (SNP) loci detected by specific-locus amplified fragment (SLAF) technology, the genome-wide genetic diversities of these two species from nine sites in Xinjiang were evaluated. D.maculates in the Muzat River (BM) and G. dybowskii in the Kaidu River (LKG) presented the lowest genetic diversity levels, whereas D. maculates in the Kumarik River (BK) and G.dybowskii in the Kashi River (LK) were just the opposite. Cluster and principal component analysis demonstrated a distant genetic affinity between D. maculates in the Tashkurgan River (BT) and other populations. Outlier SNP loci were discovered both in D. maculates and G. dybowskii. The coalescent Bayenv and latent factor mixed model (LFMM) methods showed that a total of thirteen and eighteen SNPs in D. maculates were associated with altitude and temperature gradient, respectively. No intersection was revealed in G. dybowskii. The results indicated that D. maculates was subject to much greater divergent selection pressure. A strong signal of isolation-by-distance (IBD) was detected across D. maculates (Mantel test, rs = 0.65; p = 0.05), indicating an evident geographical isolation in the Tarim River. Isolation-by-environment (IBE) analysis implied that temperature and altitude selections were more intensive in D. maculates, with greater environmental variation resulting in weak gene flow.

scholarly journals Diversity patterns of planktonic microeukaryote communities in tropical floodplain lakes based on 18S rDNA gene sequences

2019 ◽  
Vol 41 (3) ◽  
pp. 241-256 ◽  
Author(s):  
Karine Borges Machado ◽  
Cíntia Pelegrineti Targueta ◽  
Adriana Maria Antunes ◽  
Thannya Nascimento Soares ◽  
Mariana Pires de Campos Telles ◽  
...  
Keyword(s):  
18S Rdna ◽  
Environmental Variables ◽  
Geographic Distance ◽  
Floodplain Lakes ◽  
Extrinsic Factors ◽  
Biogeographic Patterns ◽  
Rdna Gene ◽  
Central Brazil ◽  
Araguaia River ◽  
18S Rdna Gene

AbstractThe aquatic microbiota plays key roles in ecosystem processes; however, the mechanisms that influence their biogeographic patterns are not yet fully understood. Using high-throughput 18S rDNA gene sequencing, we investigated the composition of planktonic microeukaryotes (organisms sampled using a 68-μm plankton net) in 27 floodplain lakes of the Araguaia River, central Brazil and explored the influence of environmental and spatial factors for communities considering taxonomic and trophic groups. Of the 807 operational taxonomic units (OTUs) observed, Chlorophyta and Charophyta were the groups with greater abundance. Beta diversity was high, and the similarity of communities decreased as the geographic distance increased. We found a shared explanation between environmental and spatial predictors for total and autotrophic microbiota. Environmental variables influence only mixotrophic microbiota. These results suggest an OTU turnover along the floodplain and a spatially structured composition. This spatial pattern can be derived from the association with extrinsic factors, such as spatially structured environmental variables, that generate spatial dependence. However, the relationship between the composition of microbiota and environmental conditions is still unclear.

scholarly journals Fine-scale genetic structure of the overwintering Chilo suppressalis in the typical bivoltine areas of northern China

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243999
Author(s):  
Ke-Xin Zhu ◽  
Shan Jiang ◽  
Lei Han ◽  
Ming-Ming Wang ◽  
Xing-Ya Wang
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Isolation By Distance ◽  
Genetic Relationships ◽  
Management Strategies ◽  
Geographic Distance ◽  
Northern China ◽  
Economic Losses ◽  
Chilo Suppressalis

The rice stem borer (RSB), Chilo suppressalis (Lepidoptera: Pyralidae), is an important agricultural pest that has caused serious economic losses in the major rice-producing areas of China. To effectively control this pest, we investigated the genetic diversity, genetic differentiation and genetic structure of 16 overwintering populations in the typical bivoltine areas of northern China based on 12 nuclear microsatellite loci. Moderate levels of genetic diversity and genetic differentiation among the studied populations were detected. Neighbour-joining dendrograms, Bayesian clustering and principal coordinate analysis (PCoA) consistently divided these populations into three genetic clades: western, eastern and northern/central. Isolation by distance (IBD) and spatial autocorrelation analyses demonstrated no correlation between genetic distance and geographic distance. Bottleneck analysis illustrated that RSB populations had not undergone severe bottleneck effects in these regions. Accordingly, our results provide new insights into the genetic relationships of overwintering RSB populations and thus contribute to developing effective management strategies for this pest.

Sign in / Sign up

Export Citation Format

Share Document