Data from: Phylogeography of sea oats (Uniola paniculata), a dune-building coastal grass in southeastern North America

We tested the hypothesis that Uniola paniculata populations are divided into eastern and western lineages, with the primary geographic break at the southern tip of Florida, as observed in codistributed animal taxa. We asked whether the geographic distribution of chloroplast DNA (cpDNA) variation in U. paniculata corresponds to 1) genetic structure in nuclear variation reported in previous studies, and 2) the geographic distribution of morphological adaptive traits reported in previous studies. We sampled 66 populations and performed phylogeographic analyses using sequence variations in maternally inherited cpDNA. We reconstructed the intraspecific phylogenetic network with TCS software and identified phylogeographic breaks in the species using Monmonier’s algorithm. Analyses identified 6 cpDNA haplotypes and 2 major lineages: eastern (Atlantic) and western (Gulf), with a phylogeographic break at the southern tip of Florida. The data suggest U. paniculata survived the last glacial maximum (LGM) in southern refugia. Following the LGM, differential leading-edge recolonization explains the current distribution of haplotypes into 2 lineages. Populations containing a haplotype from outside its native range are likely due to human-mediated transplantation. The genetic structure of cpDNA variation has weak correlation with nuclear DNA variation, and there is partial concordance between the geographic distribution of cpDNA and morphological variation.

我们验证了如下假说：正如同域分布动物类群中观测到的那样，海燕麦草（Uniola paniculata）的种群可划分为东部与西部两支系，其主要地理分界位于佛罗里达半岛南端。本研究旨在探究海燕麦草的叶绿体DNA（chloroplast DNA，cpDNA）变异的地理分布是否符合以下两项标准：1）既往研究中报道的核变异遗传结构；2）既往研究中报道的形态适应性性状的地理分布。我们共采集了66个种群样本，并利用母系遗传的cpDNA序列变异开展了系统地理学分析。我们使用TCS软件构建了种内系统发育网络，并通过Monmonier算法鉴定了该物种的系统地理分界。分析结果共鉴定出6个cpDNA单倍型以及2个主要支系：东部（大西洋）支系与西部（墨西哥湾）支系，其系统地理分界位于佛罗里达半岛南端。本研究数据表明，海燕麦草在末次冰盛期（last glacial maximum，LGM）期间于南部避难所存活。在末次冰盛期之后，差异性的前沿再定植过程解释了当前单倍型分化为两支系的分布格局。携带原生分布范围外单倍型的种群，其成因大概率为人类介导的移植活动。cpDNA变异的遗传结构与核DNA变异仅存在微弱相关性，且cpDNA的地理分布与形态变异仅存在部分一致性。