Rodríguez-Robles Javier A, Jezkova Tereza, Leal Manuel
School of Life Sciences, University of Nevada, LasVegas, 4505 Maryland Parkway, Las Vegas, NV 89154-4004, USA.
Mol Phylogenet Evol. 2008 Feb;46(2):503-14. doi: 10.1016/j.ympev.2007.11.006. Epub 2007 Nov 22.
Species with restricted geographic distributions consisting of isolated populations are particularly susceptible to extinction because these demes face an increased risk of disappearing due to environmental, demographic, and genetic stochasticity. We used partial DNA sequences of the cytochrome b (1083 bp) and ND2 (1041 bp) mitochondrial genes to investigate the phylogeography and population genetics of Anolis cooki, a threatened lizard endemic to the southwestern coast of the Caribbean Island of Puerto Rico. Maximum likelihood and Bayesian methods revealed relatively shallow genetic differentiation among 27 unique haplotypes (from 52 individuals) from the known extant populations of A. cooki in mainland Puerto Rico. Despite this pattern, specimens from the same geographic area tended to nest together. The most basal division within A. cooki is between haplotypes from the three westernmost populations (Punta Aguila, Morrillos, Playa Santa) and the remainder demes (Bahía Ballena, La Cueva, Punta Verraco). The three westernmost populations of A. cooki are separated from their conspecific demes by the Guánica Bay and the Loco River drainage system, which together may represent a physiographic barrier for A. cooki. Each population of A. cooki only has private haplotypes; in other words, there are no shared mitochondrial types between populations. Because the number of private haplotypes can be used as an indirect measure of gene flow, this finding suggests that currently there is no migration among demes, and that each is an independent demographic unit, despite the relatively short distances (ca. 2 km) that separate some of them. Pairwise F(ST) values and spatial analyses of molecular variation confirmed the existence of distinct groups of genetically defined sampling areas, and of significant molecular variation among populations within groups and within populations. The conservation status of the populations of A. cooki varies greatly. The demes from Punta Aguila, Morrillos, and Bahía Ballena inhabit protected areas, and are larger, genetically diverse, and seemingly stable. The population from Playa Santa showed a high level of genetic diversity, but it occurs in an area that has been intensively developed for residential and touristic purposes, and its long-term survival is uncertain. A. cooki is also known from Caja de Muertos, an island off the southcentral coast of Puerto Rico. Surveys conducted on September 2006 and March 2007 did not produce any specimens, and a thorough assessment of Caja de Muertos is needed to determine the present status of A. cooki on the island.
地理分布受限且由孤立种群组成的物种尤其容易灭绝，因为这些种群由于环境、种群统计学和遗传随机性面临着更高的消失风险。我们使用细胞色素b（1083 bp）和ND2（1041 bp）线粒体基因的部分DNA序列来研究库氏安乐蜥的系统地理学和种群遗传学，库氏安乐蜥是波多黎各加勒比海岛西南海岸特有的一种濒危蜥蜴。最大似然法和贝叶斯方法揭示了来自波多黎各大陆已知现存库氏安乐蜥种群的27个独特单倍型（来自52个个体）之间相对较浅的遗传分化。尽管有这种模式，但来自同一地理区域的标本往往聚在一起。库氏安乐蜥最基部的分化发生在最西部的三个种群（阿吉拉角、莫里略斯、圣塔海滩）的单倍型和其余种群（巴耶纳湾、拉库埃瓦、韦拉科角）之间。库氏安乐蜥最西部的三个种群被瓜尼卡湾和洛科河排水系统与其同种种群隔开，这两者共同可能构成了库氏安乐蜥的一个地理屏障。库氏安乐蜥的每个种群都只有私有单倍型；换句话说，不同种群之间没有共享的线粒体类型。因为私有单倍型的数量可以用作基因流动的间接指标，这一发现表明目前不同种群之间没有迁移，而且每个种群都是一个独立的种群统计学单位，尽管其中一些种群之间相隔相对较短的距离（约2公里）。成对F(ST)值和分子变异的空间分析证实了存在由遗传定义的不同采样区域组，以及组内种群之间和种群内部存在显著的分子变异。库氏安乐蜥种群的保护状况差异很大。阿吉拉角、莫里略斯和巴耶纳湾的种群栖息在保护区内，规模更大，遗传多样，似乎也很稳定。圣塔海滩的种群表现出高度的遗传多样性，但它所在的区域已被密集开发用于居住和旅游目的，其长期生存情况不确定。在波多黎各中南部海岸外的莫尔托斯岛也发现过库氏安乐蜥。2006年9月和2007年3月进行的调查没有采集到任何标本，需要对莫尔托斯岛进行全面评估以确定库氏安乐蜥在该岛的现状。
