Nourisson Coralie, Morales-Vela Benjamín, Padilla-Saldívar Janneth, Tucker Kimberly Pause, Clark Annmarie, Olivera-Gómez Leon David, Bonde Robert, McGuire Peter
El Colegio de la Frontera Sur, Av. Centenario Km 5.5, 77000 Chetumal, Quintana Roo, Mexico.
Genetica. 2011 Jul;139(7):833-42. doi: 10.1007/s10709-011-9583-z. Epub 2011 Jun 17.
The Antillean manatee (Trichechus manatus manatus) occupies the tropical coastal waters of the Greater Antilles and Caribbean, extending from Mexico along Central and South America to Brazil. Historically, manatees were abundant in Mexico, but hunting during the pre-Columbian period, the Spanish colonization and throughout the history of Mexico, has resulted in the significantly reduced population occupying Mexico today. The genetic structure, using microsatellites, shows the presence of two populations in Mexico: the Gulf of Mexico (GMx) and Chetumal Bay (ChB) on the Caribbean coast, with a zone of admixture in between. Both populations show low genetic diversity (GMx: N(A) = 2.69; H(E) = 0.41 and ChB: N(A) = 3.0; H(E) = 0.46). The lower genetic diversity found in the GMx, the largest manatee population in Mexico, is probably due to a combination of a founder effect, as this is the northern range of the sub-species of T. m. manatus, and a bottleneck event. The greater genetic diversity observed along the Caribbean coast, which also has the smallest estimated number of individuals, is possibly due to manatees that come from the GMx and Belize. There is evidence to support limited or unidirectional gene flow between these two important areas. The analyses presented here also suggest minimal evidence of a handful of individual migrants possibly between Florida and Mexico. To address management issues we suggest considering two distinct genetic populations in Mexico, one along the Caribbean coast and one in the riverine systems connected to the GMx.
安的列斯海牛（Trichechus manatus manatus）栖息于大安的列斯群岛和加勒比海的热带沿海水域，从墨西哥沿着中美洲和南美洲一直延伸到巴西。历史上，海牛在墨西哥数量众多，但在哥伦布发现美洲大陆之前的时期、西班牙殖民时期以及墨西哥整个历史进程中的捕猎，导致如今墨西哥境内的海牛数量大幅减少。利用微卫星进行的基因结构分析表明，墨西哥存在两个种群：墨西哥湾（GMx）种群和加勒比海岸的切图马尔湾（ChB）种群，两者之间存在一个混合区域。两个种群的遗传多样性都较低（GMx：等位基因数N(A)=2.69；期望杂合度H(E)=0.41；ChB：N(A)=3.0；H(E)=0.46）。在墨西哥最大的海牛种群GMx中发现的较低遗传多样性，可能是由于奠基者效应（因为这是T. m. manatus亚种的北部分布范围）和瓶颈事件共同作用的结果。在加勒比海岸观察到的遗传多样性更高，而该区域估计的个体数量也是最少的，这可能是由于来自GMx和伯利兹的海牛。有证据支持这两个重要区域之间存在有限或单向的基因流动。此处呈现的分析还表明，仅有极少量证据显示可能存在少数个体在佛罗里达和墨西哥之间迁移。为解决管理问题，我们建议考虑墨西哥的两个不同遗传种群，一个在加勒比海岸，另一个在与GMx相连的河流系统中。
