scholarly journals Forecasting eco-evolutionary dynamics in the Northern Blue butterfly (Lycaeides idas)

Author(s):  
Zachariah Gompert ◽  
Lauren Lucas

Natural selection can drive rapid evolutionary change, particularly in human-altered habitats. Rapid adaptation to global change requires standing genetic variation for ecologically important traits, but at present little is known about how much relevant genetic variation most populations possess. With this in mind, we began a long term study of genome-wide molecular evolution in a series of natural butterfly populations in the Greater Yellowstone Area (GYA) in 2012 to quantify the contribution of environment-dependent natural selection to evolution in these butterfly populations, and determine whether selection varies enough across space and time to maintain variation that could facilitate adaptation to global change. In 2018, we visited 11 focal populations to collect samples for DNA, estimate population sizes (using distance sampling and mark-release-recapture methods), and survey arthropod communities at the sites. Our analyses are ongoing, and this is a preliminary report, but thus far we have found that census population sizes are much higher than contemporary effective population sizes (though these metrics are highly correlated), and that both are independent of genetic diversity levels. These results are consistent with the hypothesis that selection plays a central role in eco-evolutionary dynamics in this system.   Featured photo from Figure 1 in report.

Author(s):  
Zachariah Gompert ◽  
Lauren Lucas

Natural selection can drive rapid evolutionary change, particularly in human-altered habitats. Rapid adaptation to global change requires standing genetic variation for ecologically important traits, but at present little is known about how much relevant genetic variation most populations possess. With this in mind, we began a long term study of genome-wide molecular evolution in a series of natural butterfly populations in the Greater Yellowstone Area in 2012 to quantify the contribution of environment-dependent natural selection to evolution in these butterfly populations, and determine whether selection varies enough across space and time to maintain variation that could facilitate adaptation to global change. In 2019, we visited 11 focal populations to collect samples for DNA and plant chemistry, estimate population sizes (mark-release-recapture methods), and survey arthropod communities at the sites. Our analyses are ongoing, and this is a preliminary report, but thus far we have found that census population sizes are much higher than contemporary effective population sizes (though these metrics are highly correlated), and that both are independent of genetic diversity levels. These results are consistent with the hypothesis that selection plays a central role in eco-evolutionary dynamics in this system.   Featured photo from figure 1 in report. 


Author(s):  
Zachariah Gompert ◽  
Lauren Lucas

Spatial and temporal variation in the strength and nature of natural selection could help explain genetic diversity in natural populations and data on short term evolutionary responses to fluctuations in temperature and rainfall could facilitate predictions of climate change impacts. In 2012, we began a long term study of genome-wide molecular evolution in populations of Lycaeides idas in the Greater Yellowstone Ecosystem (GYE). In 2016, we used distance sampling to estimate population densities of 10 butterfly populations spread across the GYE in Wyoming and Montana. In parallel, we estimated host plant cover and conducted insect community surveys at each site. We also completed a genotyping-by-sequencing survey for eight populations sampled in 2013 and 2015 to estimate contemporary variance in effective population sizes. Based on 480 samples across sites, we found significant variation in population sizes (as estimated by distance sampling) among sites and years. Host plant abundance, climate, and insect communities varied among sites but were not consistently predictive of population size. Estimates of effective population sizes among sites showed pronounced variation that was uncorrelated with genetic diversity, possibly due to widespread fluctuating selection.   Featured photo from Figure 1 in report.


Author(s):  
Zachariah Gompert ◽  
Lauren Lucas

Long term studies of wild populations indicate that natural selection can cause rapid and dramatic changes in traits, with spatial and temporal variation in the strength of selection a critical driver of genetic variation in natural populations. In 2012, we began a long term study of genome-wide molecular evolution in populations of the butterfly Lycaeides ideas in the Greater Yellowstone Area (GYA). We aimed to quantify the role of environment-dependent selection on evolution in these populations. Building on previous work, in 2017 we collected new samples, incorporated distance sampling, and surveyed the insect community at each site. We also defined the habitat boundary at anew, eleventh site. Our preliminary analyses suggest that both genetic drift and selection are important drivers in this system.   Featured photo from Figure 1 in report.


1997 ◽  
Vol 69 (2) ◽  
pp. 111-116 ◽  
Author(s):  
ZIHENG YANG

The theory developed by Takahata and colleagues for estimating the effective population size of ancestral species using homologous sequences from closely related extant species was extended to take account of variation of evolutionary rates among loci. Nuclear sequence data related to the evolution of modern humans were reanalysed and computer simulations were performed to examine the effect of rate variation on estimation of ancestral population sizes. It is found that the among-locus rate variation does not have a significant effect on estimation of the current population size when sequences from multiple loci are sampled from the same species, but does have a significant effect on estimation of the ancestral population size using sequences from different species. The effects of ancestral population size, species divergence time and among-locus rate variation are found to be highly correlated, and to achieve reliable estimates of the ancestral population size, effects of the other two factors should be estimated independently.


1989 ◽  
Vol 53 (3) ◽  
pp. 215-221 ◽  
Author(s):  
Zhao-Bang Zeng

SummaryEvolutionary consequences of natural selection, migration, genotype–environment interaction, and random genetic drift on interpopulation variation and covariation of quantitative characters are analysed in terms of a selection model that partitions natural selection into directional and stabilizing components. Without migration, interpopulation variation and covariation depend mainly on the pattern and intensities of selection among populations and the harmonic mean of effective population sizes. Both transient and equilibrium covariance structures are formulated with suitable approximations. Migration reduces the differentiation among populations, but its effect is less with genotype–environment interaction. In some special cases of genotype–environment interaction, the equilibrium interpopulation variation and covariation is independent of migration.


Author(s):  
Zachariah Gompert ◽  
Lauren Lucas

The study of evolution in natural populations has advanced our understanding of the origin and maintenance of biological diversity. For example, long term studies of wild populations indicate that natural selection can cause rapid and dramatic changes in traits, but that in some cases these evolutionary changes are quickly reversed when periodic variation in weather patterns or the biotic environment cause the optimal trait value to change (e.g., Reznick et al. 1997, Grant and Grant 2002). In fact, spatial and temporal variation in the strength and nature of natural selection could explain the high levels of genetic variation found in many natural populations (Gillespie 1994, Siepielski et al. 2009). Long term studies of evolution in the wild could also be informative for biodiversity conservation and resource management, because, for example, data on short term evolutionary responses to annual fluctuations in temperature or rainfall could be used to predict longer term evolution in response to directional climate change. Most previous research on evolution in the wild has considered one or a few observable traits or genes (e.g., Kapan 2001, Grant and Grant 2002, Barrett et al. 2008). We believe that more general conclusions regarding the rate and causes of evolutionary change in the wild and selection’s contribution to the maintenance of genetic variation could be obtained by studying genome-wide molecular evolution in a suite of natural populations. Thus, in 2012 we began a long term study of genome-wide molecular evolution in a series of natural butterfly populations in the Greater Yellowstone Area (GYA). This study will allow us to quantify the contribution of environment-dependent natural selection to evolution in these butterfly populations and determine whether selection consistently favors the same alleles across space and through time.


Author(s):  
Zachariah Gompert ◽  
Lauren Lucas

The study of evolution in natural populations has advanced our understanding of the origin and maintenance of biological diversity. For example, long term studies of wild populations indicate that natural selection can cause rapid and dramatic changes in traits, but that in some cases these evolutionary changes are quickly reversed when periodic variation in weather patterns or the biotic environment cause the optimal trait value to change (e.g., Reznick et al. 1997; Grant and Grant 2002). In fact, spatial and temporal variation in the strength and nature of natural selection could explain the high levels of genetic variation found in many natural populations (Gillespie 1994; Siepielski et al. 2009). Long term studies of evolution in the wild could also be informative for biodiversity conservation and resource management, because, for example, data on short term evolutionary responses to annual fluctuations in temperature or rainfall could be used to predict longer term evolution in response to directional climate change. Most previous research on evolution in the wild has considered one or a few observable traits or genes (Kapan 2001; Grant and Grant 2002; Barrett et al. 2008). We believe that more general conclusions regarding the rate and causes of evolutionary change in the wild and selection’s contribution to the maintenance of genetic variation could be obtained by studying genome-wide molecular evolution in a suite of natural populations. Thus, we have begun a long term study of genome-wide molecular evolution in a series of natural butterfly populations in the Greater Yellowstone Area (GYA). This study will allow us to quantify the contribution of environment-dependent natural selection to evolution in these butterfly populations and determine whether selection consistently favors the same alleles across space and through time.


2000 ◽  
Vol 51 (1) ◽  
pp. 23 ◽  
Author(s):  
Tony van den Enden ◽  
Robert W. G. White ◽  
Nicholas G. Elliott

Samples of the greenback flounder, Rhombosolea tapirina, were collected from five Tasmanian sites and from one site each off Victoria and New Zealand. Thirty enzyme-coding loci were analysed by gel electrophoresis. Seventeen loci were variable, nine of which were polymorphic in at least four samples. Average heterozygosity across all 30 loci was relatively high at 0.086 ± 0.032. There were significant genetic differences between the Australian and New Zealand samples, with a genetic distance of 0.041, which was an order of magnitude larger than that observed between any Australian samples. Samples from the west coast of Tasmania and from Victoria were genetically isolated from each other and from the remaining four Tasmanian samples; the latter showed little variation among themselves. Reductions in genetic variation (heterozygosity and alleles) were observed in two cultured cohorts when compared with the wild-caught samples, with corresponding low estimates of effective population sizes compared with putative breeding numbers. No genetic variation was detected between normal and malpigmented individuals from the same culture cohort.


2019 ◽  
Vol 11 (10) ◽  
pp. 2875-2886 ◽  
Author(s):  
Venkat Talla ◽  
Lucile Soler ◽  
Takeshi Kawakami ◽  
Vlad Dincă ◽  
Roger Vila ◽  
...  

Abstract The relative role of natural selection and genetic drift in evolution is a major topic of debate in evolutionary biology. Most knowledge spring from a small group of organisms and originate from before it was possible to generate genome-wide data on genetic variation. Hence, it is necessary to extend to a larger number of taxonomic groups, descriptive and hypothesis-based research aiming at understanding the proximate and ultimate mechanisms underlying both levels of genetic polymorphism and the efficiency of natural selection. In this study, we used data from 60 whole-genome resequenced individuals of three cryptic butterfly species (Leptidea sp.), together with novel gene annotation information and population recombination data. We characterized the overall prevalence of natural selection and investigated the effects of mutation and linked selection on regional variation in nucleotide diversity. Our analyses showed that genome-wide diversity and rate of adaptive substitutions were comparatively low, whereas nonsynonymous to synonymous polymorphism and substitution levels were comparatively high in Leptidea, suggesting small long-term effective population sizes. Still, negative selection on linked sites (background selection) has resulted in reduced nucleotide diversity in regions with relatively high gene density and low recombination rate. We also found a significant effect of mutation rate variation on levels of polymorphism. Finally, there were considerable population differences in levels of genetic diversity and pervasiveness of selection against slightly deleterious alleles, in line with expectations from differences in estimated effective population sizes.


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