Original Article
Phylogeographic patterns driven by river isolations in an island-endemic
montane plant
Shaojun Ling1,2, Juli
Caujapé-Castells3, Liang Tang1,2 and
Mingxun Ren1,2*
1Key Laboratory of Genetics and Germplasm Innovation
of Tropical Special Forest Trees and Ornamental Plants (Hainan
University), Ministry of Education, Haikou 570228, China
2Center for Terrestrial Biodiversity of the South
China Sea, Hainan University, Haikou 570228, China
3Departamento de Biodiversidad Molecular y Banco de
DNA, Jardín Botánico Canario ʻViera y Clavijoʼ – Unidad Asociada CSIC,
Cabildo de Gran Canaria, Camino del Palmeral 15, 35017 Las Palmas de
Gran Canaria, Spain
Running title : Phylogeography driven by rivers
*Corresponding author. E-mail: renmx@hainanu.edu.cnAbstract Hainan Island in south China is a key part of the globally
important Indo-Burma biodiversity hotspot, while the origin and
maintenance of its species richness remains largely unexplored. In this
study, we combined nuclear ITS and cpDNA trn L-trn F andycf 1b sequences to evaluate the genetic structure and
phylogeographic patterns of the Hainan-endemic Primulina
heterotricha (Gesneriaceae). The results showed significant
phylogeographic patterns with low within-population genetic diversity
and significant genetic differentiation among populations (Fst =
0.708 ± 0.319 and 0.826 ± 0.209 for nrDNA and cpDNA). Three clades were
identified with little gene flow (Nm << 1 for
nrDNA and cpDNA), which is supported by our STRUCTURE v.2.3.4 analyses.
Our analyses detected two vicariance events at c. 0.83 andc . 0.48 Myr, and suggest that these three genetically-separated
groups were isolated by two big rivers (Changhua River and Wanglou
River), that likely acted as barriers to gene flow. The magnitude of
isolation was positively correlated to the size of the rivers, with the
greater barrier effect associated with the larger Changhua River. Our
results highlight for the first time the critical role of riverine
isolation in the patterns of intraspecific evolution of plant
populations on Hainan Island.
KEYWORDS Biogeography, Changhua River, Isolation,
Phylogeographic patterns, Hainan Island