Population genetic structure and demography of Magnolia kobus: variety borealis is not supported genetically
Population genetic structure and demography of Magnolia kobus: variety borealis is not supported genetically
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DOI：
10.1007/s10265-019-01134-6
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发表时间：
2019-09
影响因子：
2.8
通讯作者：
I. Tamaki;Naomichi Kawashima;S. Setsuko;Jung-Hyun Lee;A. Itaya;Kyohei Yukitoshi;N. Tomaru
中科院分区：
文献类型：
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作者：
I. Tamaki;Naomichi Kawashima;S. Setsuko;Jung-Hyun Lee;A. Itaya;Kyohei Yukitoshi;N. Tomaru
形态学和遗传标记对物种的界定并不总是一致的。厚朴由两个形态上不同的变种组成，厚朴和北方木兰。后者的特点是叶片比前者大。为了保护M.在天然林中的kobusgenetic资源，形态和遗传变异之间的关系应该澄清。本研究对23个居群的紫云英进行了核微卫星、叶绿体DNA（cpDNA）序列和叶片形态性状的变异分析。kobusover the range范围of species种类.两个遗传分化的谱系，北方和南方，其地理边界估计在39°N。北方家系由两个遗传簇和一个单倍型组成，南方家系由多个遗传簇和单倍型组成。北方家系的遗传多样性显著低于南方家系。近似贝叶斯计算表明，北方和南方谱系分别经历了人口膨胀和长期稳定的人口规模。这两个谱系之间的分歧时间估计为565，000年前，没有发现分歧后两个谱系之间迁移的迹象。生态位模拟表明，在末次盛冰期日本北方的潜在分布面积很小。因此，这两个谱系在几个冰期-间冰期旋回中经历了不同的种群历史。在日本海一侧的本州中部至北方部分和北海道的种群个体具有较大的叶宽和叶面积。这些叶特征与北方变种的叶特征相一致。然而，由遗传标记（39°N）检测到的北方和南方谱系的划分与由叶片形态（36°N）检测到的不一致。因此，我们建议，varietyborealisis不支持遗传和北方和南方的谱系应单独考虑时，确定保护单位的基础上，而不是形态，但遗传标记。
Species delimitations by morphological and by genetic markers are not always congruent.Magnolia kobusconsists of two morphologically different varieties,kobusandborealis. The latter variety is characterized by larger leaves than the former. For the conservation ofM. kobusgenetic resources in natural forests, the relationships between morphological and genetic variation should be clarified. We investigated variations in nuclear microsatellites, chloroplast DNA (cpDNA) sequences and leaf morphological traits in 23 populations ofM. kobusover the range of species. Two genetically divergent lineages, northern and southern were detected and their geographical boundary was estimated to be at 39°N. The northern lineage consisted of two genetic clusters and a single cpDNA haplotype, while the southern one had multiple genetic clusters and cpDNA haplotypes. The northern lineage showed significantly lower genetic diversity than the southern. Approximate Bayesian computation indicated that the northern and southern lineages had experienced, respectively, population expansion and long-term stable population size. The divergence time between the two lineages was estimated to be 565,000 years ago and no signature of migration between the two lineages after divergence was detected. Ecological niche modeling showed that the potential distribution area in northern Japan at the last glacial maximum was very small. It is thus considered that the two lineages have experienced different population histories over several glacial-inter-glacial cycles. Individuals of populations in the central to northern part of Honshu on the Sea of Japan side and in Hokkaido had large leaf width and area. These leaf characteristics corresponded with those of varietyborealis. However, the delimitation of the northern and southern lineages detected by genetic markers (39°N) was not congruent with that detected by leaf morphologies (36°N). It is therefore suggested that varietyborealisis not supported genetically and the northern and southern lineages should be considered separately when identifying conservation units based not on morphology but on genetic markers.