Multiple glacial refugia for cool-temperate deciduoustrees in northern East Asia: the Mongolian oak as a case study

作   者：曾艳飞，王文婷，廖万金，王红芳，张大勇
期刊名称：Molecular Ecology
影响因子：6.086
卷 期 号：25
页     码：5676–5691
关键词：East Asia, ecological niche modelling, molecular variation, northern refugia, Quaternary glaciations, temperate forest
论文摘要：
In East Asia, temperate forests are predicted to have retracted southward to c. 30 N
during the last glacial maximum (LGM) based on fossil pollen data, whereas phylogeographic
studies have often suggested glacial in situ survival of cool-temperate
deciduous trees in their modern northern ranges. Here we report a study of the genetic
diversity and structure of 29 natural Mongolian oak (Quercus mongolica) populations
using 19 nuclear simple sequence repeat (nSSR) loci and four chloroplast DNA fragments.
Bayesian clustering analysis with nSSRs revealed five groups, which were
inferred by approximate Bayesian computation (ABC) to have diverged in multiple
refugia through multiple glacial–interglacial cycles. Analysis of chloroplast DNA variation
revealed four lineages that were largely but incompletely geographically disjunct.
Ecological niche modelling (ENMs) indicated a southward range shift of the oak’s distribution
at the LGM, although high suitability scores were also evident in the Changbai
Mts. (Northeast China), the Korean Peninsula, areas surrounding the Bohai Sea,
and along the coast of the Russian Far East. In addition, endemic chloroplast DNA
haplotypes and nuclear lineages occurred in high-latitude northern areas where the
ENM predicted no suitable habitat. The combined evidence from nuclear and chloroplast
DNA, and the results of the ENM clearly demonstrate that multiple northern
refugia, including cryptic ones, were maintained across the current distributional range
of the Mongolian oak during the LGM or earlier glacial periods. Though spatially limited,
postglacial expansions from these refugia have led to a pattern of decreased
genetic diversity with increasing latitude.