TY - JOUR
T1 - Genetic divergence with ongoing gene flow is maintained by the use of different hosts in phytophagous ladybird beetles genus Henosepilachna
AU - Matsubayashi, K. W.
AU - Kohyama, T. I.
AU - Kobayashi, N.
AU - Yamasaki, S.
AU - Kuwajima, M.
AU - Katakura, H.
N1 - Funding Information:
We thank Masahito T. Kimura, who provided much valuable comments on the manuscript; Kazuma Matsumoto and Kouta Furukawa, who gave information of beetle distribution; Patrik Nosil, who gave valuable suggestions on the early draft; Shogo Kikuta, Akemi Togashi for assistance to prepare experimental plants; Naoyuki Fujiyama, Issei Ohshima for helpful comments on analyses and context; Matthew H. Dick, Toru Katoh, Hiroshi Kajihara for allowing us to use molecular space. Two anonymous reviewers gave constructive and helpful comments on the manuscript. This study was supported by Grants-in-Aid to K.W.M (No. 16H06178) and H. K. (Nos. 14204081, 18207005), and by a postdoctoral fellowship from the Japan Society for the Promotion of Science (JSPS) for Young Scientists to K.W.M. (No. 10J03106).
Publisher Copyright:
© 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2017/6
Y1 - 2017/6
N2 - Adaptation to different environments can promote population divergence via natural selection even in the presence of gene flow – a phenomenon that typically occurs during ecological speciation. To elucidate how natural selection promotes and maintains population divergence during speciation, we investigated the population genetic structure, degree of gene flow and heterogeneous genomic divergence in three closely related Japanese phytophagous ladybird beetles: Henosepilachna pustulosa, H. niponica and H. yasutomii. These species act as a generalist, a wild thistle (Cirsium spp.) specialist and a blue cohosh (Caulophyllum robustum) specialist, respectively, and their ranges differ accordingly. The two specialist species widely co-occur but are reproductively isolated solely due to their high specialization to a particular host plant. Genomewide amplified fragment-length polymorphism (AFLP) markers and mitochondrial cytochrome c oxidase subunit I (COI) gene sequences demonstrated obvious genomewide divergence associated with both geographic distance and ecological divergence. However, a hybridization assessment for both AFLP loci and the mitochondrial sequences revealed a certain degree of unidirectional gene flow between the two sympatric specialist species. Principal coordinates analysis (PCoA) based on all of the variable AFLP loci demonstrated that there are genetic similarities between populations from adjacent localities irrespective of the species (i.e. host range). However, a further comparative genome scan identified a few fractions of loci representing approximately 1% of all loci as different host-associated outliers. These results suggest that these three species had a complex origin, which could be obscured by current gene flow, and that ecological divergence can be maintained with only a small fraction of the genome is related to different host use even when there is a certain degree of gene flow between sympatric species pairs.
AB - Adaptation to different environments can promote population divergence via natural selection even in the presence of gene flow – a phenomenon that typically occurs during ecological speciation. To elucidate how natural selection promotes and maintains population divergence during speciation, we investigated the population genetic structure, degree of gene flow and heterogeneous genomic divergence in three closely related Japanese phytophagous ladybird beetles: Henosepilachna pustulosa, H. niponica and H. yasutomii. These species act as a generalist, a wild thistle (Cirsium spp.) specialist and a blue cohosh (Caulophyllum robustum) specialist, respectively, and their ranges differ accordingly. The two specialist species widely co-occur but are reproductively isolated solely due to their high specialization to a particular host plant. Genomewide amplified fragment-length polymorphism (AFLP) markers and mitochondrial cytochrome c oxidase subunit I (COI) gene sequences demonstrated obvious genomewide divergence associated with both geographic distance and ecological divergence. However, a hybridization assessment for both AFLP loci and the mitochondrial sequences revealed a certain degree of unidirectional gene flow between the two sympatric specialist species. Principal coordinates analysis (PCoA) based on all of the variable AFLP loci demonstrated that there are genetic similarities between populations from adjacent localities irrespective of the species (i.e. host range). However, a further comparative genome scan identified a few fractions of loci representing approximately 1% of all loci as different host-associated outliers. These results suggest that these three species had a complex origin, which could be obscured by current gene flow, and that ecological divergence can be maintained with only a small fraction of the genome is related to different host use even when there is a certain degree of gene flow between sympatric species pairs.
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U2 - 10.1111/jeb.13071
DO - 10.1111/jeb.13071
M3 - Article
C2 - 28306172
AN - SCOPUS:85018297021
SN - 1010-061X
VL - 30
SP - 1110
EP - 1123
JO - Journal of Evolutionary Biology
JF - Journal of Evolutionary Biology
IS - 6
ER -