Divergence maintained by climatic selection despite recurrent gene flow: a case study of Castanopsis carlesii (Fagaceae)

Local adaptation to different environments has the potential to maintain divergence between populations despite recurrent gene flow and is an important driver for generating biological diversity. In this study, we investigate the role of adaptation in the maintenance of two parapatric varieties of a...

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Published inMolecular ecology Vol. 25; no. 18; pp. 4580 - 4592
Main Authors Sun, Ye, Surget-Groba, Yann, Gao, Shaoxiong
Format Journal Article
LanguageEnglish
Published England Blackwell Publishing Ltd 01.09.2016
Subjects
Castanopsis
Castanopsis carlesii
China
Climate
divergence
DNA, Chloroplast - genetics
Evolution & development
Fagaceae
Fagaceae - genetics
Gene Flow
Genetic diversity
Genetic Variation
Genetics, Population
niche reconstruction
restriction site-associated DNA
secondary contact
Trees
Castanopsis carlesii
gene flow
divergence
restriction site-associated DNA
secondary contact
niche reconstruction
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Summary:Local adaptation to different environments has the potential to maintain divergence between populations despite recurrent gene flow and is an important driver for generating biological diversity. In this study, we investigate the role of adaptation in the maintenance of two parapatric varieties of a forest tree. We used sequence variation of chloroplastic DNA and restriction site‐associated DNA to investigate the genetic structure of two varieties of Castanopsis carlesii in subtropical China and relate it to climatic variation. We used niche reconstruction methods to investigate niche differentiation between the two varieties and to estimate the past distribution of this species. A deep divergence was observed between the two varieties, but evidence of introgression and genetic admixture was detected in two phenotypically and geographically intermediate populations. Niche reconstruction suggests that the distribution of the two varieties was disjunct during periods of global cooling and that the two varieties occupy significantly different niches. The genetic structure was mainly driven by environmental factors, and 13 outlier loci under divergent selection were correlated with climatic variation. These results suggest that the two varieties evolved in allopatry and came back into secondary contact after the last glacial maximum and that they are an evolutionary example of divergence maintained by climatic selection despite recurrent gene flow.
Bibliography:Table S1. Prior distribution of each parameter in approximate Bayesian computations. Table S2. Genotypes at 649 RAD loci used for bayescan, geste and structure analysis. Table S3. 649 SNPs used for the diyabc analysis. Table S4. Posterior probabilities of six scenarios computed by direct estimation and logistic regression. Fig. S1. Results of the Jackknife test to evaluate the importance of the four selected variables in the modelling of the current potential distribution of Castanopsis carlesii. Fig. S2. Response curves given by maxent showing how each variable affects the prediction of species distribution model. Fig. S3. Relationships of seven chloroplast haplotypes revealed in this study. Fig. S4. The prior and posterior distributions for each parameter of scenario 6 in approximate Bayesian computations.
National Natural Science Foundation of China - No. 31370668; No. 31170512
ark:/67375/WNG-M0RTBDW9-W
ArticleID:MEC13764
istex:951451619E1AB55F9930878F435F7EB1701C90D5
Guangzhou Branch of the Supercomputing Center of Chinese Academy of Sciences
ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:0962-1083
1365-294X
DOI:10.1111/mec.13764