scholarly journals Ready on arrival: Standing variation at a chromosomal inversion contributes to rapid adaptation in an invasive marine crab

2021 ◽  
Author(s):  
Joshua A Thia
Keyword(s):  
Chromosomal Inversion ◽  
Rapid Adaptation ◽  
Standing Variation

scholarly journals Rapid parallel evolution of standing variation in a single, complex, genomic region is associated with life history in steelhead/rainbow trout

2014 ◽  
Vol 281 (1783) ◽  
pp. 20140012 ◽  
Author(s):  
Devon E. Pearse ◽  
Michael R. Miller ◽  
Alicia Abadía-Cardoso ◽  
John Carlos Garza
Keyword(s):  
Life History ◽  
Rainbow Trout ◽  
Parallel Evolution ◽  
Genomic Region ◽  
Life History Strategies ◽  
Strong Linkage Disequilibrium ◽  
Rapid Adaptation ◽  
Life History Variation ◽  
Standing Variation ◽  
Genomic Regions

Rapid adaptation to novel environments may drive changes in genomic regions through natural selection. Such changes may be population-specific or, alternatively, may involve parallel evolution of the same genomic region in multiple populations, if that region contains genes or co-adapted gene complexes affecting the selected trait(s). Both quantitative and population genetic approaches have identified associations between specific genomic regions and the anadromous (steelhead) and resident (rainbow trout) life-history strategies of Oncorhynchus mykiss . Here, we use genotype data from 95 single nucleotide polymorphisms and show that the distribution of variation in a large region of one chromosome, Omy5, is strongly associated with life-history differentiation in multiple above-barrier populations of rainbow trout and their anadromous steelhead ancestors. The associated loci are in strong linkage disequilibrium, suggesting the presence of a chromosomal inversion or other rearrangement limiting recombination. These results provide the first evidence of a common genomic basis for life-history variation in O. mykiss in a geographically diverse set of populations and extend our knowledge of the heritable basis of rapid adaptation of complex traits in novel habitats.

scholarly journals Cryptic genetic variation underpins rapid adaptation to ocean acidification

2019 ◽  
Author(s):  
M. C. Bitter ◽  
L. Kapsenberg ◽  
J.-P. Gattuso ◽  
C. A. Pfister
Keyword(s):  
Climate Change ◽  
Genetic Variation ◽  
Natural Populations ◽  
Future Climate Change ◽  
Rapid Adaptation ◽  
Larval Size ◽  
Larval Population ◽  
Cryptic Genetic Variation ◽  
Standing Variation ◽  
Seawater Ph

AbstractGlobal climate change has intensified the need to assess the capacity for natural populations to adapt to abrupt shifts in the environment. Reductions in seawater pH constitute a conspicuous stressor associated with increasing atmospheric carbon dioxide that is affecting ecosystems throughout the world’s oceans. Here, we quantify the phenotypic and genetic modifications associated with rapid adaptation to reduced seawater pH in the marine mussel, Mytilus galloprovincialis. We reared a genetically diverse larval population in ambient and extreme low pH conditions (pHT 8.1 and 7.4) and tracked changes in the larval size and allele frequency distributions through settlement. Additionally, we separated larvae by size to link a fitness-related trait to its underlying genetic background in each treatment. Both phenotypic and genetic data show that M. galloprovincialis can evolve in response to a decrease in seawater pH. This process is polygenic and characterized by genotype-environment interactions, suggesting the role of cryptic genetic variation in adaptation to future climate change. Holistically, this work provides insight into the processes underpinning rapid evolution, and demonstrates the importance of maintaining standing variation within natural populations to bolster species’ adaptive capacity as global change progresses.

scholarly journals De Novo Mutation and Rapid Protein (Co-)evolution during Meiotic Adaptation in Arabidopsis arenosa

2021 ◽  
Author(s):  
Magdalena Bohutínská ◽  
Vinzenz Handrick ◽  
Levi Yant ◽  
Roswitha Schmickl ◽  
Filip Kolář ◽  
...  
Keyword(s):  
Amino Acid ◽  
Positive Selection ◽  
De Novo ◽  
Empirical Studies ◽  
De Novo Mutation ◽  
Rapid Adaptation ◽  
De Novo Mutations ◽  
Standing Variation ◽  
Arabidopsis Arenosa ◽  
Meiosis Genes

Abstract A sudden shift in environment or cellular context necessitates rapid adaptation. A dramatic example is genome duplication, which leads to polyploidy. In such situations, the waiting time for new mutations might be prohibitive; theoretical and empirical studies suggest that rapid adaptation will largely rely on standing variation already present in source populations. Here, we investigate the evolution of meiosis proteins in Arabidopsis arenosa, some of which were previously implicated in adaptation to polyploidy, and in a diploid, habitat. A striking and unexplained feature of prior results was the large number of amino acid changes in multiple interacting proteins, especially in the relatively young tetraploid. Here, we investigate whether selection on meiosis genes is found in other lineages, how the polyploid may have accumulated so many differences, and whether derived variants were selected from standing variation. We use a range-wide sample of 145 resequenced genomes of diploid and tetraploid A. arenosa, with new genome assemblies. We confirmed signals of positive selection in the polyploid and diploid lineages they were previously reported in and find additional meiosis genes with evidence of selection. We show that the polyploid lineage stands out both qualitatively and quantitatively. Compared with diploids, meiosis proteins in the polyploid have more amino acid changes and a higher proportion affecting more strongly conserved sites. We find evidence that in tetraploids, positive selection may have commonly acted on de novo mutations. Several tests provide hints that coevolution, and in some cases, multinucleotide mutations, might contribute to rapid accumulation of changes in meiotic proteins.

scholarly journals Standing genetic variation fuels rapid adaptation to ocean acidification

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
M. C. Bitter ◽  
L. Kapsenberg ◽  
J.-P. Gattuso ◽  
C. A. Pfister
Keyword(s):  
Genetic Variation ◽  
Global Change ◽  
Global Climate ◽  
Shell Growth ◽  
Natural Populations ◽  
Rapid Adaptation ◽  
Shell Size ◽  
Larval Population ◽  
Standing Variation ◽  
Seawater Ph

AbstractGlobal climate change has intensified the need to assess the capacity for natural populations to adapt to abrupt shifts in the environment. Reductions in seawater pH constitute a conspicuous global change stressor that is affecting marine ecosystems globally. Here, we quantify the phenotypic and genetic modifications associated with rapid adaptation to reduced seawater pH in the Mediterranean mussel, Mytilus galloprovincialis. We reared a genetically diverse larval population in two pH treatments (pHT 8.1 and 7.4) and tracked changes in the shell-size distribution and genetic variation through settlement. Additionally, we identified differences in the signatures of selection on shell growth in each pH environment. Both phenotypic and genetic data show that standing variation can facilitate adaptation to declines in seawater pH. This work provides insight into the processes underpinning rapid evolution, and demonstrates the importance of maintaining variation within natural populations to bolster species’ adaptive capacity as global change progresses.

scholarly journals Ability of a bacterial chromosome segment to invert is dictated by included material rather than flanking sequence.

Genetics ◽  
1991 ◽  
Vol 129 (4) ◽  
pp. 1021-1032 ◽  
Author(s):  
M J Mahan ◽  
J R Roth
Keyword(s):  
Homologous Recombination ◽  
Parent Strain ◽  
Genetic Material ◽  
Chromosomal Inversion ◽  
Chromosome Segment ◽  
Bacterial Chromosome ◽  
Flanking Sequence ◽  
Flanking Sequences ◽  
Almost All

Abstract Homologous recombination between sequences present in inverse order within the same chromosome can result in inversion formation. We have previously shown that inverse order sequences at some sites (permissive) recombine to generate the expected inversion; no inversions are found when the same inverse order sequences flank other (nonpermissive) regions of the chromosome. In hopes of defining how permissive and nonpermissive intervals are determined, we have constructed a strain that carries a large chromosomal inversion. Using this inversion mutant as the parent strain, we have determined the "permissivity" of a series of chromosomal sites for secondary inversions. For the set of intervals tested, permissivity seems to be dictated by the nature of the genetic material present within the chromosomal interval being tested rather than the flanking sequences or orientation of this material in the chromosome. Almost all permissive intervals include the origin or terminus of replication. We suggest that the rules for recovery of inversions reflect mechanistic restrictions on the occurrence of inversions rather than lethal consequences of the completed rearrangement.

Work-from-home during COVID-19: Accounting for the care economy to build back better

2021 ◽  
pp. 103530462098360
Author(s):  
Fiona Jenkins ◽  
Julie Smith
Keyword(s):  
Economic Activity ◽  
Public Investment ◽  
Economic Life ◽  
Rapid Adaptation ◽  
Policy Makers ◽  
Jel Codes ◽  
Work From Home ◽  
Adaptive Capabilities ◽  
Care Economy ◽  
A Site

In the COVID-19 pandemic, people’s dwellings suddenly became a predominant site of economic activity. We argue that, predictably, policy-makers and employers took the home for granted as a background support of economic life. Acting as if home is a cost-less resource that is free for appropriation in an emergency, ignoring how home functions as a site of gendered relations of care and labour, and assuming home is a largely harmonious site, all shaped the invisibility of the imposition. Taking employee flexibility for granted and presenting work-from-home as a privilege offered by generous employers assumed rapid adaptation. As Australia emerges from lockdown, ‘building back better’ to meet future shocks entails better supporting adaptive capabilities of workers in the care economy, and of homes that have likewise played an unacknowledged role as buffer and shelter for the economy. Investing in infrastructure capable of providing a more equitable basis for future resilience is urgent to reap the benefits that work-from-home offers. This article points to the need for rethinking public investment and infrastructure priorities for economic recovery and reconstruction in the light of a gender perspective on COVID-19 ‘lockdown’ experience. JEL Codes: E01, E22, J24

scholarly journals DNA Sequence Variation and the Recombinational Landscape in Drosophila pseudoobscura: A Study of the Second Chromosome

Genetics ◽  
1999 ◽  
Vol 153 (2) ◽  
pp. 859-869 ◽  
Author(s):  
Martha T Hamblin ◽  
Charles F Aquadro
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Dna Sequence ◽  
Sequence Variation ◽  
Population Expansion ◽  
Drosophila Pseudoobscura ◽  
Effective Population ◽  
Standing Variation ◽  
Dna Sequence Polymorphism ◽  
Slightly Deleterious Mutations

Abstract The relationship between rates of recombination and DNA sequence polymorphism was analyzed for the second chromosome of Drosophila pseudoobscura. We constructed integrated genetic and physical maps of this chromosome using molecular markers at 10 loci spanning most of its physical length. The total length of the map was 128.2 cM, almost twice that of the homologous chromosome arm (3R) in D. melanogaster. There appears to be very little centromeric suppression of recombination, and rates of recombination are quite uniform across most of the chromosome. Levels of sequence variation (θW, based on the number of segregating sites) at seven loci (tropomyosin 1, Rhodopsin 3, Rhodopsin 1, bicoid, Xanthine dehydrogenase, Myosin light chain 1, and ribosomal protein 49) varied from 0.0036 to 0.0167. Generally consistent with earlier studies, the average estimate of θW at total sites is 1.5-fold higher than that in D. melanogaster, while average θW at silent sites is almost 3-fold higher. These estimates of variation were analyzed in the context of a background selection model under the same parameters of mutation rate and selection as have been proposed for D. melanogaster. It is likely that a significant fraction of the higher level of sequence variation in D. pseudoobscura can be explained by differences in regional rates of recombination rather than a larger species-level effective population size. However, the distribution of variation among synonymous, nonsynonymous, and noncoding sites appears to be quite different between the species, making direct comparisons of neutral variation, and hence inferences about effective population size, difficult. Tajima’s D statistics for 6 out of the 7 loci surveyed are negative, suggesting that D. pseudoobscura may have experienced a rapid population expansion in the recent past or, alternatively, that slightly deleterious mutations constitute an important component of standing variation in this species.

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