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Trans‐lineage polymorphism and nonbifurcating diversification of the genus Picea
Author(s) -
Feng Shuo,
Ru Dafu,
Sun Yongshuai,
Mao Kangshan,
Milne Richard,
Liu Jianquan
Publication year - 2019
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.15590
Subject(s) - coalescent theory , biology , phylogenetic tree , lineage (genetic) , introgression , evolutionary biology , phylogenetics , gene flow , disjunct , taxon , genetics , gene , botany , genetic variation , population , demography , sociology
Summary Nonbifurcating divergence caused by introgressive hybridization is continuously reported for groups of closely related species. In this study, we aimed to reconstruct the genome‐scale classification of deep lineages of the conifer genus Picea , establish their phylogenetic relationships and test the bifurcating hypothesis between deeply branching lineages based on genomic data. We sequenced the transcriptomes of 35 individuals of 27 taxa covering all main lineages of the genus. Four major lineages, comprising three to 12 taxa each, largely consistent with morphological evidence, were recovered across the coalescent and integrated nuclear phylogeny. However, many of the individual gene trees recovered contradict one another. Moreover, the well‐supported coalescent tree inferred here differs from previous studies based on various DNA markers, with respect to topology and inter‐lineage relationships. We identified the shared polymorphisms between four major lineages. ABBA–BABA tests confirmed the inter‐lineage gene flow and thus violated the bifurcating divergence model. Gene flow occurred more frequently between lineages distributed in the same continent than those disjunct between continents. Our results indicate that introgression and nonbifurcating diversification apply, even between deeply branching lineages of the conifer genus Picea .