Colihueque Nelson, Estay Francisco J, Crespo Julio E, Arriagada Aldo, Baessolo Luisa, Canales-Aguirre Cristian B, Marín Javier, Carrasco René
Laboratorio de Biología Molecular y Citogenética, Departamento de Ciencias Biológicas y Biodiversidad, Universidad de Los Lagos, Osorno, Chile.
Gerencia de Investigación y Desarrollo, Piscícola Huililco Ltda., Pucón, Chile.
Front Genet. 2019 Dec 20;10:1212. doi: 10.3389/fgene.2019.01212. eCollection 2019.
Numerous self-sustaining naturalized or introduced populations of rainbow trout () are widely distributed throughout the freshwaters of southern Chile. In this study, analysis of the mitochondrial DNA control region (CR) marker was conducted to investigate the level of genetic divergence among populations and their phylogenetic relationships with respect to native lineages. This information provided a framework to interpret the genetic structure and origin that was shaped during historical trout introduction efforts. To this end, we analyzed eleven naturalized populations of lakes and rivers from five basins. The CR marker revealed five haplotypes. The overall haplotype () and nucleotide () diversities were 0.684 ± 0.030 and 0.00460 ± 0.00012, respectively. Global was 0.169, with several pairwise estimates showing significant differences ( < 0.05). The exact test of population differentiation corroborated this result ( < 0.001). Significant geographic structure was found ( < 0.05), with variations explained primarily by differences within populations (61.65%) and among group basins (20.82%). Maximum likelihood phylogenetic analysis resolved two distinct clades with medium bootstrap support when naturalized populations were aligned in conjunction with reference native lineages. The haplotype network revealed a close association between naturalized populations and four main haplotypes representative of three native ecotypes or lineages from western North America (rainbow trout, steelhead trout and redband trout). These results indicate a genetic population structuring for naturalized rainbow trout from southern Chile and an origin probably represented by multiple lineages sources. Thus, mitochondrial DNA data strongly suggest that stocking of rainbow trout from different origins may have occurred during or after the initial introduction efforts.
大量自我维持的虹鳟（）归化种群或引入种群广泛分布于智利南部的淡水区域。在本研究中，我们对线粒体DNA控制区（CR）标记进行了分析，以调查各虹鳟种群间的遗传分化水平及其与本地谱系的系统发育关系。这些信息为解释在历史上虹鳟引入过程中形成的遗传结构和起源提供了一个框架。为此，我们分析了来自五个流域的11个湖泊和河流的归化种群。CR标记揭示了五种单倍型。总体单倍型（）和核苷酸（）多样性分别为0.684±0.030和0.00460±0.00012。全局为0.169，几个成对估计显示出显著差异（<0.05）。种群分化的确切检验证实了这一结果（<0.001）。发现了显著的地理结构（<0.05），变异主要由种群内部差异（61.65%）和组间流域差异（20.82%）解释。当归化种群与参考本地谱系一起排列时，最大似然系统发育分析在中等自展支持下解析出两个不同的分支。单倍型网络揭示了归化种群与代表北美西部三种本地生态型或谱系（虹鳟、硬头鳟和红斑鳟）的四种主要单倍型之间的密切关联。这些结果表明智利南部归化虹鳟存在遗传种群结构，其起源可能由多个谱系来源代表。因此，线粒体DNA数据强烈表明，在最初引入之后或期间可能发生了来自不同起源的虹鳟放流。
