Abstract
To understand the origin and evolutionary history, and the geographical and historical causes for the formation of the current distribution pattern of Lquidambar formosana Hance, we investigated the phylogeography by using chloroplasts DNA (cpDNA) non-coding sequences and species distribution models (SDM). Four cpDNA intergenic spacer regions were amplified and sequenced for 251 individuals from 25 populations covering most of its geographical range in China. A total of 20 haplotypes were recovered. The species had a high level of chloroplast genetic variation (Ht = 0.909 ± 0.0192) and a significant phylogeographical structure (genetic differentiation takes into account distances among haplotypes (Nst) = 0.730 > population differentiation that does not consider distances among haplotypes (Gst) = 0.645; p < 0.05), whereas the genetic variation within populations (Hs = 0.323 ± 0.0553) was low. The variation of haplotype mainly occurred among populations (genetic differentiation coefficient (Fst) = 0.73012). The low genetic diversity within populations may be attributed to the restricted gene flow (Nm = 0.18). The time of the most recent common ancestor for clade V mostly distributed in Southwestern China, Central China, Qinling and Dabieshan mountains was 10.30 Ma (95% Highest posterior density (HPD): 9.74–15.28) dating back to the middle Miocene, which revealed the genetic structure of L. formosana was of ancient origin. These results indicated that dramatic changes since the Miocene may have driven the ancestors of L. formosana to retreat from the high latitudes of the Northern Hemisphere to subtropical China in which the establishment and initial intensification of the Asian monsoon provided conditions for their ecological requirements. This scenario was confirmed by the fossil record. SDM results indicated there were no contraction–expansion dynamics, and there was a stable range since the last interglacial period (LIG, 130 kya). Compared with the population expansion detected by Fu’s Fs value and the mismatch distribution, we speculated the expansion time may happen before the interglacial period. Evidence supporting L. formosana was the ancient origin and table range since the last interglacial period.
Highlights
Asia’s climate has experienced dramatic changes since the Miocene and the global climate cooling (17–15 Ma) after the Miocene [1,2]
The total chloroplasts DNA (cpDNA) haplotype diversity (Ht = 0.909) detected in our study was considerably higher than the average value (Ht = 0.67) of 170 species using cpDNA markers reported by Petit [41]
Dramatic changes since the Miocene and associated climate cooling changes may have driven the ancestors of L. formosana to retreat from the high latitudes of the Northern Hemisphere to subtropical China in which the establishment and initial intensification of the Asian monsoon provided conditions for their ecological requirements
Summary
Asia’s climate has experienced dramatic changes since the Miocene and the global climate cooling (17–15 Ma) after the Miocene [1,2]. The dramatic changes included intensification of East Asian. Further uplift of the QTP caused intensifications of the East Asian summer and winter monsoons (15 Ma [6], 10–8 Ma, and 3.6–2.6 Ma [7]). A few studies on the evolutionary histories of relict plants traced back to the Middle and Early Miocene, a period that had experienced dramatic climate and topographic changes in Asia [1,2,7,9]. Compared to other temperate/subtropical regions, such as southern Europe and the southeastern United States where genetic structure is often of recent origin and related to refugia dynamics, the ancient origin of the relict plant in subtropical China may have experienced less extreme demographic fluctuations [9]. Phylogeographical studies of subtropical China are mainly focused on rare and endangered plants, such as Sargentodoxa cuneate (Oliv.) [11], Davidia involucrate Baill. [12], Cercidiphyllum japonicum. [13]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
