title: Adaptive and nonadaptive genome size evolution in Karst endemic flora of China.
abstract: Genome size variation is of fundamental biological importance and has been a longstanding puzzle in evolutionary biology. Several hypotheses for genome size evolution including neutral, maladaptive, and adaptive models have been proposed, but the relative importance of these models remains controversial. Primulina is a genus that is highly diversified in the Karst region of southern China, where genome size variation and the underlying evolutionary mechanisms are poorly understood. We reconstructed the phylogeny of Primulina using DNA sequences for 104 species and determined the genome sizes of 101 species. We examined the phylogenetic signal in genome size variation, and tested the fit to different evolutionary models and for correlations with variation in latitude and specific leaf area (SLA). The results showed that genome size, SLA and latitudinal variation all displayed strong phylogenetic signals, but were best explained by different evolutionary models. Furthermore, significant positive relationships were detected between genome size and SLA and between genome size and latitude. Our study is the first to investigate genome size evolution on such a comprehensive scale and in the Karst region flora. We conclude that genome size in Primulina is phylogenetically conserved but its variation among species is a combined outcome of both neutral and adaptive evolution.
authors.affiliation: Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Kang
authors.affiliation: Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.|University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Tao
authors.affiliation: Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Ren
authors.affiliation: Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.|University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Qingwen
authors.initials: Q
authors.lastname: Qi
authors.affiliation: Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695-7612, USA.
authors.forename: Qiu-Yun
authors.initials: QY
authors.lastname: Xiang
authors.affiliation: Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.
authors.forename: Hongwen
authors.initials: H
authors.lastname: Huang
mesh_terms: D002681:China; D032461:Chromosomes, Plant / Q000235:genetics*; D018744:DNA, Plant / Q000235:genetics; D019143:Evolution, Molecular; D059646:Genome Size; D018745:Genome, Plant / Q000235:genetics*; D019684:Magnoliopsida / Q000235:genetics*; D010802:Phylogeny; D011123:Polyploidy
chemical_list: D018744:DNA, Plant
keywords: Karst flora; Primulina; chromosome number; correlated evolution; flow cytometry; genome size evolution; phylogeny-based comparative analysis; specific leaf area