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Adaptive divergence with gene flow in incipient speciation of M iscanthus floridulus / sinensis complex ( P oaceae)
Author(s) -
Huang ChaoLi,
Ho ChuanWen,
Chiang YuChung,
Shigemoto Yasumasa,
Hsu TsaiWen,
Hwang ChiChuan,
Ge XueJun,
Chen Charles,
Wu TaiHan,
Chou ChangHung,
Huang HaoJen,
Gojobori Takashi,
Osada Naoki,
Chiang TzenYuh
Publication year - 2014
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12676
Subject(s) - allopatric speciation , parapatric speciation , ecotype , biology , gene flow , ecological speciation , genetic algorithm , evolutionary biology , incipient speciation , disruptive selection , sympatry , sympatric speciation , ecology , natural selection , gene , genetics , selection (genetic algorithm) , genetic variation , population , demography , artificial intelligence , sociology , computer science
Summary Young incipient species provide ideal materials for untangling the process of ecological speciation in the presence of gene flow. The M iscanthus floridulus / sinensis complex exhibits diverse phenotypic and ecological differences despite recent divergence (approximately 1.59 million years ago). To elucidate the process of genetic differentiation during early stages of ecological speciation, we analyzed genomic divergence in the M iscanthus complex using 72 randomly selected genes from a newly assembled transcriptome. In this study, rampant gene flow was detected between species, estimated as M = 3.36 × 10 −9 to 1.20 × 10 −6 , resulting in contradicting phylogenies across loci. Nevertheless, beast analyses revealed the species identity and the effects of extrinsic cohesive forces that counteracted the non‐stop introgression. As expected, early in speciation with gene flow, only 3–13 loci were highly diverged; two to five outliers (approximately 2.78–6.94% of the genome) were characterized by strong linkage disequilibrium, and asymmetrically distributed among ecotypes, indicating footprints of diversifying selection. In conclusion, ecological speciation of incipient species of M iscanthus probably followed the parapatric model, whereas allopatric speciation cannot be completely ruled out, especially between the geographically isolated northern and southern M . sinensis , for which no significant gene flow across oceanic barriers was detected. Divergence between local ecotypes in early‐stage speciation began at a few genomic regions under the influence of natural selection and divergence hitchhiking that overcame gene flow.