The most ubiquitous, abundant, and invasive turtle on Earth, Trachemys scripta elegans (TSE, "red-eared slider"), is one of four taxa in a clade that is native to the USA and adjacent Mexico (three subspecies of Trachemys scripta plus Trachemys gaigeae). The present range-wide study of this clade is based on 173 known-locality mtDNA sequences combined with ddRAD libraries for 43 samples emphasizing the western part of the range of TSE, its contact with that of T. gaigeae, and anthropogenic hybrids between TSE and T. s. scripta. The data presented here are the first to sample the TSE × T. s. scripta intergrade zone or TSE × T. s. scripta crosses from introduced turtles. In the western part of its range (New Mexico and Texas), most samples of TSE from the Pecos River have mtDNA haplotypes matching T. gaigeae. Structure analysis of SNPs from the ddRAD show evidence of genetic admixture between T. gaigeae and TSE in all included samples from the Rio Grande and Pecos River. These populations also exhibit T. gaigeae-like head stripes, i.e., a postorbital marking that does not reach the eye. The genetic and morphological data are thereby reconciled, as both suggest that these TSE are intergrades. We recommend that these populations continue to be considered TSE, despite the admixture with T. gaigeae. In the Eastern United States, some samples of the morphologically intermediate subspecies T. s. troostii are not genetically distinct from TSE and some samples share morphological characters and genetic affinities with T. s. scripta. Based on these observations we conclude that the taxon T. s. troostii represents intergrades between TSE and T. s. scripta and should not be considered a valid taxon. Near the already established part of the intergrade zone between TSE and T. s. scripta, TSE mtDNA haplotypes have naturally introgressed into typical-looking samples of T. s. scripta in Georgia. Hybrids between introduced TSE and T. s. scripta are also confirmed deeper within the natural range of T. s. scripta in South Carolina and Virginia. Given the examples of feral hybrids deep within its range shown here and elsewhere, the threat of genetic pollution of T. s. scripta by feral TSE is established.

中文翻译：

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在美国的红耳滑块（Trachemys scripta elegans）的遗传变异和混合。

Trachemys scripta elegans（TSE，“红耳滑子”）是地球上最普遍，最丰富和最具侵略性的乌龟，是美国和邻国墨西哥的一个进化枝中的四个类群之一（Trachys scripta的三个亚种Trageys gaigeae）。目前对该进化枝的全范围研究是基于173个已知位置的mtDNA序列与ddRAD库相结合的43个样本，这些样本强调了TSE范围的西部，与T. gaigeae的接触以及TSE和TSE之间的人为杂交体T. s。脚本。此处提供的数据是第一个对TSE×T.s进行采样的数据。scripta过渡带或TSE×T。scripta与引进的海龟杂交。在其范围的西部（新墨西哥州和德克萨斯州），大多数来自Pecos河的TSE样品均具有与T. gaigeae相匹配的mtDNA单倍型。来自ddRAD的SNPs的结构分析表明，在所有来自里奥格兰德河和佩科斯河的样本中，T。gaigeae和TSE之间存在遗传混合的证据。这些种群还表现出盖氏锥虫状的头条纹，即眼眶后的标记没有到达眼睛。遗传和形态学数据因此得以调和，因为两者都表明这些TSE是等级间的。我们建议将这些种群与T. gaigeae混为一谈，继续将其视为TSE。在美国东部，一些形态上处于中间形态的亚种T. s。troostii与TSE在遗传上没有区别，一些样品与T. s具有形态特征和遗传亲和力。脚本。基于这些观察，我们得出结论：分类单元T。troostii代表TSE和T. s之间的过渡。脚本，不应视为有效的分类单元。在TSE和T.s之间过渡区域的已建立部分附近。TSE mtDNA单倍体自然已经渗入了T. s的典型外观样本中。佐治亚州的scripta。引入的TSE和T.s之间的混合体。在T. s的自然范围内，scripta也被证实更深。南卡罗来纳州和弗吉尼亚州的scripta。鉴于这里和其他地方显示的在其范围内深处的野生杂种的实例，T。s的遗传污染的威胁。建立了由野生TSE编写的scripta。在T. s的自然范围内，scripta也被证实更深。南卡罗来纳州和弗吉尼亚州的scripta。鉴于这里和其他地方显示的在其范围内深处的野生杂种的实例，T。s的遗传污染的威胁。建立了由野生TSE编写的scripta。在T. s的自然范围内，scripta也被证实更深。南卡罗来纳州和弗吉尼亚州的scripta。鉴于这里和其他地方显示的在其范围内深处的野生杂种的实例，T。s的遗传污染的威胁。建立了由野生TSE编写的scripta。