Harrison Elizabeth, Trexler Joel C, Collins Timothy M, Vazquez-Domínguez Ella, Razo-Mendivil Ulises, Matamoros Wilfredo A, Barrientos Christian
Department of Biological Sciences, Florida International University, Miami, Florida, United States of America.
Departamento de Ecología de la Biodiversidad, Universidad Nacional Autónoma de México, México DF, México.
PLoS One. 2014 Sep 3;9(9):e104173. doi: 10.1371/journal.pone.0104173. eCollection 2014.
The number and diversity of source populations may influence the genetic diversity of newly introduced populations and affect the likelihood of their establishment and spread. We used the cytochrome b mitochondrial gene and nuclear microsatellite loci to identify the sources of a successful invader in southern Florida, USA, Cichlasoma urophthalmus (Mayan cichlid). Our cytochrome b data supported an introduction from Guatemala, while our microsatellite data suggested movement of Mayan Cichlids from the upper Yucatán Peninsula to Guatemala and introductions from Guatemala and Belize to Florida. The mismatch between mitochondrial and nuclear genomes suggests admixture of a female lineage from Guatemala, where all individuals were fixed for the mitochondrial haplotype found in the introduced population, and a more diverse but also relatively small number of individuals from Belize. The Florida cytochrome b haplotype appears to be absent from Belize (0 out of 136 fish screened from Belize had this haplotype). Genetic structure within the Florida population was minimal, indicating a panmictic population, while Mexican and Central American samples displayed more genetic subdivision. Individuals from the Upper Yucatán Peninsula and the Petén region of Guatemala were more genetically similar to each other than to fish from nearby sites and movement of Mayan Cichlids between these regions occurred thousands of generations ago, suggestive of pre-Columbian human transportation of Mayan Cichlids through this region. Mayan Cichlids present a rare example of cytonuclear disequilibrium and reduced genetic diversity in the introduced population that persists more than 30 years (at least 7-8 generations) after introduction. We suggest that hybridization occurred in ornamental fish farms in Florida and may contribute their establishment in the novel habitat. Hybridization prior to release may contribute to other successful invasions.
源种群的数量和多样性可能会影响新引入种群的遗传多样性，并影响其建立和扩散的可能性。我们使用细胞色素b线粒体基因和核微卫星位点来确定美国佛罗里达州南部一种成功的入侵物种——眼点丽鱼（玛雅丽鱼）的来源。我们的细胞色素b数据支持其从危地马拉引入，而微卫星数据表明玛雅丽鱼从尤卡坦半岛北部迁移到危地马拉，并从危地马拉和伯利兹引入到佛罗里达州。线粒体和核基因组之间的不匹配表明，来自危地马拉的一个雌性谱系与来自伯利兹的数量相对较少但更为多样的个体发生了混合，在危地马拉所有个体都固定为引入种群中发现的线粒体单倍型。伯利兹似乎不存在佛罗里达州的细胞色素b单倍型（从伯利兹筛选的136条鱼中没有一条具有这种单倍型）。佛罗里达州种群内的遗传结构最小，表明是一个随机交配的种群，而墨西哥和中美洲的样本显示出更多的遗传细分。尤卡坦半岛北部和危地马拉佩滕地区的个体彼此之间的遗传相似性高于与附近地点的鱼类，玛雅丽鱼在这些地区之间的迁移发生在数千代之前，这表明玛雅丽鱼在哥伦布发现美洲大陆之前就被人类通过该地区运输。玛雅丽鱼是一个罕见的例子，即引入种群中的细胞核-细胞质不平衡和遗传多样性降低，这种情况在引入后持续了30多年（至少7-8代）。我们认为杂交发生在佛罗里达州的观赏鱼养殖场，这可能有助于它们在新栖息地的建立。释放前的杂交可能有助于其他成功的入侵。
