scholarly journals Genetic Diversity of Spatially Isolated Populations of Coconut Caterpillar, Opisina arenosella (Oecophoridae: Lepidoptera)

2019 ◽  
Vol 8 (01) ◽  
pp. 1760-1772
Author(s):  
K. Muralimohan ◽  
B. Shivanna ◽  
N. Nagesha
Keyword(s):  
Genetic Diversity ◽  
Isolated Populations ◽  
Opisina Arenosella

scholarly journals Whole genome sequencing reveals high differentiation, low levels of genetic diversity and short runs of homozygosity among Swedish wels catfish

Heredity ◽  
2021 ◽  
Author(s):  
Axel Jensen ◽  
Mette Lillie ◽  
Kristofer Bergström ◽  
Per Larsson ◽  
Jacob Höglund
Keyword(s):  
Genetic Diversity ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Whole Genome Sequencing Data ◽  
Peripheral Populations ◽  
Whole Genome ◽  
Runs Of Homozygosity ◽  
Sequencing Data ◽  
Isolated Populations ◽  
Native Populations

AbstractThe use of genetic markers in the context of conservation is largely being outcompeted by whole-genome data. Comparative studies between the two are sparse, and the knowledge about potential effects of this methodology shift is limited. Here, we used whole-genome sequencing data to assess the genetic status of peripheral populations of the wels catfish (Silurus glanis), and discuss the results in light of a recent microsatellite study of the same populations. The Swedish populations of the wels catfish have suffered from severe declines during the last centuries and persists in only a few isolated water systems. Fragmented populations generally are at greater risk of extinction, for example due to loss of genetic diversity, and may thus require conservation actions. We sequenced individuals from the three remaining native populations (Båven, Emån, and Möckeln) and one reintroduced population of admixed origin (Helge å), and found that genetic diversity was highest in Emån but low overall, with strong differentiation among the populations. No signature of recent inbreeding was found, but a considerable number of short runs of homozygosity were present in all populations, likely linked to historically small population sizes and bottleneck events. Genetic substructure within any of the native populations was at best weak. Individuals from the admixed population Helge å shared most genetic ancestry with the Båven population (72%). Our results are largely in agreement with the microsatellite study, and stresses the need to protect these isolated populations at the northern edge of the distribution of the species.

scholarly journals Small population size and low genomic diversity have no effect on fitness in experimental translocations of a wild fish

2019 ◽  
Vol 286 (1916) ◽  
pp. 20191989 ◽  
Author(s):  
M. C. Yates ◽  
E. Bowles ◽  
D. J. Fraser
Keyword(s):  
Genetic Diversity ◽  
Body Size ◽  
Population Size ◽  
Brook Trout ◽  
Habitat Degradation ◽  
Species Conservation ◽  
Empirical Work ◽  
Genomic Diversity ◽  
Effective Population ◽  
Isolated Populations

Little empirical work in nature has quantified how wild populations with varying effective population sizes and genetic diversity perform when exposed to a gradient of ecologically important environmental conditions. To achieve this, juvenile brook trout from 12 isolated populations or closed metapopulations that differ substantially in population size and genetic diversity were transplanted to previously fishless ponds spanning a wide gradient of ecologically important variables. We evaluated the effect of genome-wide variation, effective population size ( N e ), pond habitat, and initial body size on two fitness correlates (survival and growth). Genetic variables had no effect on either fitness correlate, which was determined primarily by habitat (pond temperature, depth, and pH) and initial body size. These results suggest that some vertebrate populations with low genomic diversity, low N e , and long-term isolation can represent important sources of variation and are capable of maintaining fitness in, and ultimately persisting and adapting to, changing environments. Our results also reinforce the paramount importance of improving available habitat and slowing habitat degradation for species conservation.

Inbreeding and loss of genetic diversity increase extinction risk

2019 ◽  
pp. 31-48
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Inbreeding Depression ◽  
Environmental Changes ◽  
Extinction Risk ◽  
Raw Material ◽  
Heterozygote Advantage ◽  
Isolated Populations ◽  
Survival And Reproduction ◽  
Loss Of Genetic Diversity ◽  
Harmful Effects

Inbreeding reduces survival and reproduction (i.e. it causes inbreeding depression), and thereby increases extinction risk. Inbreeding depression is due to increased homozygosity for harmful alleles and at loci exhibiting heterozygote advantage. Inbreeding depression is nearly universal in sexually reproducing organisms that are diploid or have higher ploidies. Impacts of inbreeding are generally greater in species that naturally outbreed than those that inbreed, in stressful than benign environments, and for fitness than peripheral traits. Harmful effects accumulate across the life cycle, resulting in devastating effects on total fitness in outbreeding species.Species face ubiquitous environmental change and must adapt or they will go extinct. Genetic diversity is the raw material required for evolutionary adaptation. However, loss of genetic diversity is unavoidable in small isolated populations, diminishing their capacity to evolve in response to environmental changes, and thereby increasing extinction risk.

scholarly journals Population Genomics of Bettongia lesueur: Admixing Increases Genetic Diversity with no Evidence of Outbreeding Depression

Genes ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 851 ◽  
Author(s):  
Kate Rick ◽  
Kym Ottewell ◽  
Cheryl Lohr ◽  
Rujiporn Thavornkanlapachai ◽  
Margaret Byrne ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Threatened Species ◽  
Population Genomics ◽  
Fold Increase ◽  
Recruitment Rate ◽  
Outbreeding Depression ◽  
Nucleotide Polymorphisms ◽  
Isolated Populations ◽  
Genomic Markers ◽  
Founder Populations

Small and isolated populations are subject to the loss of genetic variation as a consequence of inbreeding and genetic drift, which in turn, can affect the fitness and long-term viability of populations. Translocations can be used as an effective conservation tool to combat this loss of genetic diversity through establishing new populations of threatened species, and to increase total population size. Releasing animals from multiple genetically diverged sources is one method to optimize genetic diversity in translocated populations. However, admixture as a conservation tool is rarely utilized due to the risks of outbreeding depression. Using high-resolution genomic markers through double-digest restriction site-associated sequencing (ddRAD-seq) and life history data collected over nine years of monitoring, this study investigates the genetic and fitness consequences of admixing two genetically-distinct subspecies of Bettongia lesueur in a conservation translocation. Using single nucleotide polymorphisms (SNPs) identified from 215 individuals from multiple generations, we found an almost 2-fold increase in genetic diversity in the admixed translocation population compared to the founder populations, and this was maintained over time. Furthermore, hybrid class did not significantly impact on survivorship or the recruitment rate and therefore we found no indication of outbreeding depression. This study demonstrates the beneficial application of mixing multiple source populations in the conservation of threatened species for minimizing inbreeding and enhancing adaptive potential and overall fitness.

The Origin of Isolated Populations of the Mountain Weevil, Liparus glabrirostris—The Flagship Species for Riparian Habitats

2020 ◽  
Author(s):  
Dorota Lachowska-Cierlik ◽  
Krzysztof Zając ◽  
Miłosz A Mazur ◽  
Arkadiusz Sikora ◽  
Daniel Kubisz ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Glacial Refugia ◽  
Species Range ◽  
Flagship Species ◽  
Isolated Populations ◽  
The Carpathians ◽  
The North ◽  
Baltic Coast ◽  
Riparian Habitats ◽  
The Baltic

Abstract Liparus glabrirostris is one of the largest European weevils, and it has been recently proposed as the flagship species for threatened riparian habitats in the mountains. For effective conservation of its populations (and associated habitats), it is crucial to understand its history, contemporary distribution, genetic diversity and predict changes in the range, including its highly isolated populations on the Baltic coast. Here, we examined numerous populations of L. glabrirostris across almost the entire species range using phylogeography and species niche modeling (SNM) approaches. Analyses of mtDNA and nucDNA markers revealed the existence of 2 major mitochondrial lineages generally separated between 1) the Alpine region and 2) the Bohemian Massif, the Carpathians, and the Baltic coast areas. Genetic diversity in nuclear genes was more complicated with no clear division between populations. The origin of Baltic populations was derived from the Carpathians, but there were probably multiple expansion events to the north. SNM suggested the existence of glacial refugia for L. glabrirostris, mainly in the Alps and the Southern Carpathians. Current predictions of species range were found to be generally congruent with zoogeographic data; however, the Baltic coast was not really supported as a suitable area for L. glabrirostris. An important prediction of future distribution (2050–2070 CE) suggests a shrinkage of the L. glabrirostris range and extinction of some of its populations (particularly those isolated on lower altitudes). Based on the aforementioned data, proposals for the protection of this species are proposed, including the designation of several evolutionary units of conservation importance.

scholarly journals Associative Overdominance and Negative Epistasis Shape Genome-Wide Ancestry Landscape in Supplemented Fish Populations

Genes ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 524
Author(s):  
Maeva Leitwein ◽  
Hugo Cayuela ◽  
Louis Bernatchez
Keyword(s):  
Genetic Diversity ◽  
Genetic Drift ◽  
Recombination Rate ◽  
Management Strategies ◽  
Population Level ◽  
Negative Effects ◽  
Isolated Populations ◽  
Positive Effects ◽  
Genome Wide ◽  
Negative Epistasis

The interplay between recombination rate, genetic drift and selection modulates variation in genome-wide ancestry. Understanding the selective processes at play is of prime importance toward predicting potential beneficial or negative effects of supplementation with domestic strains (i.e., human-introduced strains). In a system of lacustrine populations supplemented with a single domestic strain, we documented how population genetic diversity and stocking intensity produced lake-specific patterns of domestic ancestry by taking the species’ local recombination rate into consideration. We used 552 Brook Charr (Salvelinus fontinalis) from 22 small lacustrine populations, genotyped at ~32,400 mapped SNPs. We observed highly variable patterns of domestic ancestry between each of the 22 populations without any consistency in introgression patterns of the domestic ancestry. Our results suggest that such lake-specific ancestry patterns were mainly due to variable associative overdominance (AOD) effects among populations (i.e., potential positive effects due to the masking of possible deleterious alleles in low recombining regions). Signatures of AOD effects were also emphasized by highly variable patterns of genetic diversity among and within lakes, potentially driven by predominant genetic drift in those small isolated populations. Local negative effects such as negative epistasis (i.e., potential genetic incompatibilities between the native and the introduced population) potentially reflecting precursory signs of outbreeding depression were also observed at a chromosomal scale. Consequently, in order to improve conservation practices and management strategies, it became necessary to assess the consequences of supplementation at the population level by taking into account both genetic diversity and stocking intensity when available.

Genetic diversity, compatibility patterns and seed quality in isolated populations of Cypripedium calceolus (Orchidaceae)

2011 ◽  
Vol 13 (1) ◽  
pp. 89-98 ◽  
Author(s):  
Henrik Æ. Pedersen ◽  
Hanne N. Rasmussen ◽  
Imalka M. Kahandawala ◽  
Michael F. Fay
Keyword(s):  
Genetic Diversity ◽  
Seed Quality ◽  
Isolated Populations ◽  
Cypripedium Calceolus

scholarly journals PSIII-15 Genetic variability of Russian domestic reindeer populations (Rangifer Tarandus) by microsatellites

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 237-238
Author(s):  
Veronika R Kharzinova ◽  
Arsen V Dotsev ◽  
Anastasiya D Solovieva ◽  
Valeriy I Fedorov ◽  
Larisa D Shimit ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variability ◽  
Indigenous Peoples ◽  
Rangifer Tarandus ◽  
R Package ◽  
Komi Republic ◽  
Middle Level ◽  
Taiga Zone ◽  
Isolated Populations ◽  
Mountain Taiga

Abstract Domestic reindeer are bred across the Russian tundra from the Kola Peninsula to Chukotka and in the mountain-taiga zone. To understand the genetic diversity and population structure of domestic reindeer, 528 individuals were analyzed using 14 microsatellites. The sample included the Nenets breed of the Komi Republic (NEN_K, n = 42), Nenets (NEN_N, n = 148), Yamalo-Nenets (NEN_Y, n = 46), Archangelsk (NEN_A, n = 47), Murmansk (NEN_M, n = 43), Taymyr (NEN_T, n = 52) regions; the Even (EVN, n = 33), the Evenk (EVK, n = 31), the Chukotka (CHUY, n = 33) breeds of Yakutia; the Chukotka breed (CHU, n = 40) of Chukotka Region; the Tuvinian (TUV, n = 32) and Mongolian (MGL, n = 21) populations of the Tuva Republic and Mongolia. Calculations were done in R package “diveRsity,” software SplitsTree 4.14.6., Structure 2.3.4. Possibly due to permanent exchanges with animals among farms of the Nenets region and thus introduction of “foreign” alleles into the herds, a higher level of genetic diversity was found in NEN_N (HE=0.699; AR =6.086). All groups had a significant homozygote excess with the maximal value of FIS in geographically isolated populations MGL (0.326) and TUV (0.229). Neighbor-Net tree showed formation of three main clusters according to breed origin and breeding region: (1) the Nenets reindeer from different regions, (2) three breeds of Yakutia and (3) TUV and MGL populations. CHU branched individually with a distance from others. At K=11 of STRUCTURE, we observed a clear clustering of CHU, MGL, TUV, NEN_T. A middle level of admixture was detected in NEN_A, NEN_Y, NEN_M and NEN_N with NEN_K and CHUY with EVN/EVK, which formed one cluster. Here, we obtained more detailed information on genetic variability of Russian domestic reindeer, which would assist to fill current gaps in knowledge about this essential species for many indigenous peoples of the Far North. The study was funded by the RSF within Project no. 16-16-10068-P.

Sign in / Sign up

Export Citation Format

Share Document