Phylogeography of Pulsatilla cernua (Ranunculaceae), a grassland species, in Japan.

Asuka Takaishi,Hajime Ikeda,Akiko Soejima,Noriyuki Fujii,Zoya V Kozhevnikova,Andrey E Kozhevnikov

doi:10.1002/ece3.5298

Abstract

The genetic diversity and structure of Pulsatilla cernua, a continental‐grassland relict, were investigated using variations in chloroplast DNA (cpDNA) and microsatellites of nuclear DNA. In the analyses of three cpDNA regions, 17 haplotypes were found in 24 populations of P. cernua from Japan, Korea, and Russia. Although the route and time of migration between the continent of Asia and Japan could not be well resolved, the cpDNA haplotype network suggests the existence of several ancient lineages in Japan and a recent secondary migration from Japan to the continent. Microsatellite analyses did not indicate genetic structure among the Japanese populations, indicating the existence of gene flow across the distribution area until recently. These results indicate that the present fragmentation of P. cernua in Japan may reflect a rapid, recent reduction from a previously large, continuous distribution.

Highlights

Recent phylogeographic studies have explained historical changes in species distribution based on the genetic structure of extant spe‐ cies (Avise, 2000, 2004 etc.)
Even though East Asia was primarily free of ice sheets during the last gla‐ cial period, climatic oscillations during the Quaternary influenced the distribution of vegeta‐ tion (Harrison, Yu, Takahara, & Prentice, 2001; Qiu, Fu, & Comes, 2011)
The distribution ranges of most plants in the Japanese Archipelago have repeatedly shifted following climatic changes during the Quaternary (Ikeda, Carlsen, Fujii, Brochmann, & Setoguchi, 2012; Kubota, Kusumoto, Shiono, & Tanaka, 2017; Yoshida, Kudo, Shimada, Hashizume, & Ono, 2016). Because their range shifts in the archipelago interacted with the neighboring con‐ tinent of Asia as well as associated islands (Chiang et al, 2014; Fujii, Ueda, Watano, & Shimizu, 1997; Ikeda, Higashi, Yakubov, Barkalov, & Setoguchi, 2014; Lee, Lee, & Choi, 2013; Nakamura et al, 2014; Sakaguchi et al, 2012), elucidating the historical interaction with the continent and surrounding islands is necessary to understand the or‐ igin of Japanese flora

Summary

| INTRODUCTION

Recent phylogeographic studies have explained historical changes in species distribution based on the genetic structure of extant spe‐ cies (Avise, 2000, 2004 etc.). Continent, they commonly occur in meadows and constitute tem‐ perate grassland vegetation that is widely spread across northeast‐ ern China Their continental range is likely the place of origin of the Mansen plants (Murata, 1988; Tabata, 1997). In Japan, most of these plants occur in the temperate southwestern part of the archipelago and are not found on the northernmost large island of Hokkaido (Hotta, 1974; Koizumi, 1931; Murata, 1988) Based on their pres‐ ent distribution in Japan, it is hypothesized that these plants mi‐ grated to Japan via the Korean Peninsula (Hotta, 1974; Kitamura, 1957; Murata, 1988; Tabata, 1997). Presl., a Mansen plant (Hotta, 1974; Murata, 1977, 1988), is a perennial herb that grows in the sunny grasslands of low mountains and river floodplains of Honshu, Shikoku, and Kyushu This species has a relatively wide distribution in Japan, from Kyushu to the northern part of Honshu.

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| MATERIALS AND METHODS

| DISCUSSION

Findings

CONFLICT OF INTEREST