Westward range expansion from middle latitudes explains the Mississippi River discontinuity in a forest herb of eastern North America
Westward range expansion from middle latitudes explains the Mississippi River discontinuity in a forest herb of eastern North America
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中纬度地区向西扩张解释了北美东部森林草本植物中密西西比河的不连续性
DOI：
10.1111/mec.15650
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发表时间：
2020
影响因子：
4.9
通讯作者：
Busch, Jeremiah W.
中科院分区：
文献类型：
--
作者：
Prior, Carly J.;Layman, Nathan C.;Koski, Matthew H.;Galloway, Laura F.;Busch, Jeremiah W.
人们通常认为温带植物已经从主要的南方避难所向北扩展了它们的地理范围。这一假设的证据是混合在北美东部的物种，并有越来越多的支持殖民地从中纬度。我们研究了RADseq基因座的全基因组变异模式，以检验有关北美森林草本植物（美洲风铃草）范围扩展的假设。首先，确定了遗传分化的空间格局。然后估计系统发育关系和分歧时间。还研究了遗传漂变的空间特征，以确定最近分布区扩展的方向性及其地理起源。最后，空间明确的情况下，植物在整个景观的传播进行了比较，使用人口突变参数和田岛的D变化。我们发现了强大的纵向细分，与人口集群成组西部和东部的密西西比河。虽然东南部地区可能是一个多样化的更新世避难所的一部分，但几乎没有证据表明，范围扩张涉及这些南部地区的创始人。相反，遗传多样性的下降和稀有等位基因的丧失支持了从阿巴拉契亚山脉南部附近的中纬度避难所向西殖民的浪潮，随后从密西西比河谷（0.51- 127万年前）的更新世集结地扩张。这些分析表明，从中纬度地区的垫脚石殖民是北美东部物种分布范围扩大的重要机制。这项研究进一步证明了群体遗传学作为一种工具来推断生物在地理范围扩展期间所走的路线的实用性。
It is often expected that temperate plants have expanded their geographical ranges northward from primarily southern refugia. Evidence for this hypothesis is mixed in eastern North American species, and there is increasing support for colonization from middle latitudes. We studied genome‐wide patterns of variation in RADseq loci to test hypotheses concerning range expansion in a North American forest herb (Campanula americana). First, spatial patterns of genetic differentiation were determined. Then phylogenetic relationships and divergence times were estimated. Spatial signatures of genetic drift were also studied to identify the directionality of recent range expansion and its geographical origins. Finally, spatially explicit scenarios for the spread of plants across the landscape were compared, using variation in the population mutation parameter and Tajima'sD. We found strong longitudinal subdivision, with populations clustering into groups west and east of the Mississippi River. While the southeastern region was probably part of a diverse Pleistocene refugium, there is little evidence that range expansion involved founders from these southern locales. Instead, declines in genetic diversity and the loss of rare alleles support a westward colonization wave from a middle latitude refugium near the southern Appalachian Mountains, with subsequent expansion from a Pleistocene staging ground in the Mississippi River Valley (0.51–1.27 million years ago). These analyses implicate stepping stone colonization from middle latitudes as an important mechanism of species range expansion in eastern North America. This study further demonstrates the utility of population genetics as a tool to infer the routes travelled by organisms during geographical range expansion.
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影响因子：
3.3
作者：
J. K. Pritchard;Matthew Stephens;Peter Donnelly
通讯作者：
J. K. Pritchard;Matthew Stephens;Peter Donnelly
影响因子：
56.9
作者：
Galloway, Laura F.;Etterson, Julie R.
通讯作者：
Etterson, Julie R.
影响因子：
1.4
作者：
Austerlitz, F;JungMuller, B;Gouyon, PH
通讯作者：
Gouyon, PH
DOI：
10.1073/pnas.1901656116
发表时间：
2019-04-23
影响因子：
11.1
作者：
Bemmels, Jordan B.;Knowles, L. Lacey;Dick, Christopher W.
通讯作者：
Dick, Christopher W.
影响因子：
3.3
作者：
Slatkin, Montgomery;Excoffier, Laurent
通讯作者：
Excoffier, Laurent