Strong genetic differentiation but not local adaptation toward the range limit of a coastal dune plant

Evolution ◽  
2016 ◽  
Vol 70 (11) ◽  
pp. 2520-2536 ◽  
Author(s):  
Karen E. Samis ◽  
Adriana López-Villalobos ◽  
Christopher G. Eckert
2020 ◽  
Vol 3 (1) ◽  
pp. 12
Author(s):  
José Marcos Torres-Valverde ◽  
José Ciro Hernández-Díaz ◽  
Artemio Carrillo-Parra ◽  
Eduardo Mendoza-Maya ◽  
Christian Wehenkel

The three Mexican spruces’ distributions are fragmented, which could lead to phenological, morphological and genetic differentiation, partially caused by local adaptation. In this study, we examined the effect that climatic variables had on the survival and growth of 5641 Picea seedlings, coming from eight seed provenances of three species and produced in identical nursery conditions. The respective responses of each species and provenance can be considered as a proxy of the genetic differentiation and adaptation of each population. A cluster analysis revealed: (i) significant differences in genetic quantitative traits among the three Picea species and (ii) significant correlations between genetic quantitative traits and climatic factors.


2022 ◽  
Author(s):  
Tiago da Silva Ribeiro ◽  
José A Galván ◽  
John E Pool

Local adaptation can lead to elevated genetic differentiation at the targeted genetic variant and nearby sites. Selective sweeps come in different forms, and depending on the initial and final frequencies of a favored variant, very different patterns of genetic variation may be produced. If local selection favors an existing variant that had already recombined onto multiple genetic backgrounds, then the width of elevated genetic differentiation (high FST) may be too narrow to detect using a typical windowed genome scan, even if the targeted variant becomes highly differentiated. We therefore used a simulation approach to investigate the power of SNP-level FST (specifically, the maximum SNP FST value within a window) to detect diverse scenarios of local adaptation, and compared it against whole-window FST and the Comparative Haplotype Identity statistic. We found that SNP FST had superior power to detect complete or mostly complete soft sweeps, but lesser power than window-wide statistics to detect partial hard sweeps. To investigate the relative enrichment and nature of SNP FST outliers from real data, we applied the two FST statistics to a panel of Drosophila melanogaster populations. We found that SNP FST had a genome-wide enrichment of outliers compared to demographic expectations, and though it yielded a lesser enrichment than window FST, it detected mostly unique outlier genes and functional categories. Our results suggest that SNP FST is highly complementary to typical window-based approaches for detecting local adaptation, and merits inclusion in future genome scans and methodologies.


2014 ◽  
Vol 7 (2) ◽  
pp. 101-114 ◽  
Author(s):  
A. K. Brunbjerg ◽  
J. Cavender-Bares ◽  
W. L. Eiserhardt ◽  
R. Ejrnaes ◽  
L. W. Aarssen ◽  
...  

Author(s):  
Daniela Chequer Charan ◽  
Carolina Pometti ◽  
Mariano Cony ◽  
Juan Cesar Vilardi ◽  
Beatriz O Saidman ◽  
...  

Abstract Prosopis chilensis (Molina) Stuntz (Leguminosae) is a valuable native species in Argentina included in the Prosopis Management Programme. Natural provenances show important height and shape differentiation throughout their distribution in the Monte Desert. The availability of progeny trials provides an opportunity to quantify genetic differentiation among provenances and test the relative importance of demographic vs adaptive processes on morphological variation. We quantified both genetic and quantitative differentiation of neutral markers and five economically important traits, respectively, among four provenances in a provenance-progeny trial. We aimed to quantify the genetic basis of variations in height, basal diameter, tree shape, spine length and biomass. Two hypotheses were tested: (1) economically important traits have significant heritability, and (2) the phenotypic variation among provenances is the result of local adaptation to particular environmental conditions. Our results indicate that most morphological variation was found among individuals within families (~95 per cent). The h2 estimates were heterogeneous among traits and ranged from low (0 for number of stems) to moderate (0.22 and 0.28 for spine length and biomass, respectively). Variance among families (~5 per cent) was evenly distributed within and among provenances. Morphological differentiation among provenances was low, but significant, and could be attributed mainly to individuals from Villa Unión. Based on molecular markers, genetic differentiation among provenances was low and significant (FST = 0.03; P = 5 × 10−4) but was able to differentiate the groups from Villa Unión, Fiambalá and Mogna-Chilecito. Neutrality tests were conducted using the FST–QST test and DJSOST and δGREGORIUS alternative coefficients of differentiation. Neutrality tests yielded no evidence of local adaptation and were rather consistent in showing a trend toward stabilizing selection, particularly for spine length. The selection strategy for breeding programmes should depend on the trait to be improved and should consider both provenance and familiar information. Considering an intra-familiar ranking is encouraged in order to maximize the genetic gain. Additionally, in order to recover germplasm provenance diversity, based on morphological and microsatellite results, our recommendation would be to include seeds from individuals from at least the Villa Unión, Fiambalá and Mogna-Chilecito areas.


2020 ◽  
Author(s):  
Godfrey Kinyori Wagutu ◽  
Xiangrong Fan ◽  
Wenlong Fu ◽  
Wei Li ◽  
Yuanyuan Chen

AbstractGlobal aquatic habitats are undergoing rapid degradation and fragmentation as a result of land-use change and climate change. Understanding the genetic variability and adaptive potential of aquatic plant species is thus important for conservation purposes. In this study, we investigated the role of environment, landscape heterogeneity and geographical distance in shaping the genetic structure of 28 natural populations of Zizania latifolia (Griseb.) Turcz. Ex Stapf in China based on 25 microsatellite markers. Genetic structure was investigated by analysis of molecular variance (AMOVA), estimation of FST, Bayesian clustering and Thermodynamic Integration (TI) methods. Isolation by environment (IBE), isolation by resistance (IBR) and isolation by distance (IBD) hypotheses were compared using a reciprocal causal model (RCM). Further, generalized linear models and spatially explicit mixed models, by using geographic, landscape and genetic variables, were developed to elucidate the role of environment in driving Z. latifolia genetic diversity. The genetic differentiation across all populations was high: FST = 0.579; Øpt = 0.578. RCM exclusively supported IBE in shaping genetic structuring, only partial support for IBR, but not for IBD. Maximum temperature of the warmest month and precipitation seasonality were the plausible parameters responsible for genetic diversity. After controlling for spatial effect and landscape complexity, precipitation seasonality was significantly associated with genetic diversity. Based on these findings, genetic structure of Z. latifolia across China seem to be as a result of local adaptation. Environmental gradient and topographical barriers, rather than geographical isolation, influence genetic differentiation of aquatic species across China resulting in instances of local adaptation.


2020 ◽  
Author(s):  
Kun Guo ◽  
Chen Chen ◽  
Xiao-Fang Liang ◽  
Yan-Fu Qu ◽  
Xiang Ji

Abstract Background: Identifying the factors that contribute to divergence among populations in mate preferences is important for understanding of the manner in which premating reproductive isolation might arise and how this isolation may in turn contribute to the evolutionary process of population divergence. Here, we offered female northern grass lizards (Takydromus septentrionalis) a choice of males between their own population and another four populations to test whether the preferences that females display in the mating trials correlate with phenotypic adaptation to local environments, or to the neutral genetic distance measured by divergence of mitochondrial DNA sequence loci. Results: Females showed a strong preference for native over foreign males. Females that mated with native versus foreign males did not differ from each other in mating latency, or copulation duration. From results of the structural equation modelling we knew that: 1) geographical distance directly contributed to genetic differentiation and environmental dissimilarity; 2) genetic differentiation and environmental dissimilarity indirectly contributed to female mate preference, largely through their effects on morphological divergence; and 3) females judged mates by body shape (appearance) and discriminated more strongly against morphologically less familiar allopatric males.Conclusions: Local adaptation rather than neutral genetic distance influences female mate preference in T. septentrionalis. The tendency to avoid mating with foreign males may indicate that, in T. septentrionalis, local adaptations are more valuable than genetic novelties. Our results highlight the importance of comprehensive studies integrating ecological, molecular and behavioral approaches to understand population divergence in female mate preferences as the consequence of local adaptations.


2022 ◽  
Vol 1 (1) ◽  
Author(s):  
S Volis ◽  
I Shulgina ◽  
B Dyuzgenbekova

Environmental variation can be large across a wide range of spatial scales resulting in complex patterns of local adaptation across species ranges. We analyzed the scale, genetic mechanism and direct climatic causes of local adaptation in a widely distributed grass Hordeum spontaneum. We performed artificial crosses of maternal plants representing the same Negev desert population with plants originating elsewhere. Pollen donors were plants from other Negev desert populations, non-desert Israeli populations sampled along an aridity gradient, and accessions covering the entire species range. Our study included planting of inter-population hybrids under favorable and simulated desert experimental conditions, followed by analysis of their performance, variation in adaptive traits and relationship with climatic parameters at sampling locations. The combined results of parental phenotypic variation and performance of hybrids were consistent with local selection, reflecting the importance of both regional and local climates. The adaptive genetic differentiation of barley desert populations had a complex architecture. None of the three effects (additive, dominance and epistasis) were fully responsible for this differentiation. Although genetic effects not related to extrinsic selection appear to contribute to genetic differentiation in barley, epistatic effects arising from local selection clearly predominated. The short-term effect of gene flow by pollen was generally negative, indicating that a majority of the new allele combinations created by recombination were maladaptive. However, the long-term effect of occasional pollen flow from other desert populations appears to be positive, as some new recombined genotypes were superior in fitness to the maternal plants even in the F2 generation.


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