Laboratorio de Genética de Poblaciones Molecular-Biología Evolutiva, Unidad de Genética, Departamento de Biología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, Colombia.
Instituto Nacional de Biodiversidad (INABIO), Quito, Ecuador.
Mitochondrial DNA A DNA Mapp Seq Anal. 2020 Jul;31(5):190-208. doi: 10.1080/24701394.2020.1769088. Epub 2020 May 29.
One of the top carnivores in the Andean mountains is the Andean bear (, Ursidae), the only bear in South America. This is a flagship and key umbrella species in Ecuador because its conservation has a positive impact on the conservation of many other species in the Andes. But to preserve, first one must know the genetic characteristics of a species, among other things. For this, we analyzed six mitochondrial genes and seven nuclear DNA microsatellites of 108 Andean bear specimens sampled throughout Ecuador. We adopted three strategies for analyzing the data: by Province, by Region (north vs south), and by Cordillera. Four main results were obtained. First, the mitochondrial genetic diversity levels were elevated, but there were no differences in genetic diversity by Province or by Cordillera. By Regions, southern Ecuador had higher genetic diversity levels than to northern Ecuador. The genetic diversity for the microsatellites was only medium for the Andean bear at this country. Second, there was clear and significant evidence of female population expansions, for the overall sample, by Province, Region, and Cordillera. This population expansion was determined to have occurred in the time interval of 30,000-20,000 years ago (YA), during the last phase of the Pleistocene. We detected a population decrease to have occurred more recently, within the last 5000 years. It continued until about 300-200 YA when a population increase was again detected. Third, there were, practically, no phylogeographic pattern nor genetic differentiation among Andean bear populations in Ecuador by Province or by Cordillera for either mitochondrial or microsatellite markers. There was a little more genetic differentiation between northern and southern areas. Fourth, there was no trace of significant spatial genetic structure for the Andean bear in Ecuador in agreement with the genetic differentiation analyses. This shows that the Andean Cordilleras in this country did not present an obstacle to the dispersion of this species. Therefore, all of the Andean bear specimens in Ecuador should be treated as a unique Management Unit (MU) for conservation purposes, differently to that determined for other countries as Colombia.
安第斯山脉的顶级肉食动物之一是安第斯熊（Ursidae），这是南美洲唯一的熊。在厄瓜多尔，这种熊是旗舰物种和关键伞护物种，因为保护它对安第斯山脉的许多其他物种的保护有积极影响。但是，要保护物种，首先必须了解其遗传特征等。为此，我们分析了在厄瓜多尔各地采集的 108 只安第斯熊样本的六个线粒体基因和七个核 DNA 微卫星。我们采用了三种数据分析策略：按省份、按区域（北与南）和按山脉。得到了四个主要结果。首先，线粒体遗传多样性水平较高，但按省份或山脉划分时没有遗传多样性差异。按区域划分，厄瓜多尔南部的遗传多样性水平高于北部。该国的安第斯熊的微卫星遗传多样性水平仅为中等。其次，总体样本、按省份、区域和山脉划分时，都有明显且显著的雌性种群扩张证据。该种群扩张发生在距今 3 万至 2 万年前（末次冰期）。我们检测到最近发生了种群减少，发生在过去的 5000 年里。这一直持续到大约 300-200 年前，然后再次检测到种群增加。第三，对于线粒体或微卫星标记，厄瓜多尔的安第斯熊种群在省份或山脉之间没有明显的系统地理模式或遗传分化。北部和南部地区之间存在略多的遗传分化。第四，安第斯熊在厄瓜多尔没有明显的空间遗传结构，这与遗传分化分析一致。这表明该国的安第斯山脉没有成为该物种扩散的障碍。因此，所有在厄瓜多尔的安第斯熊样本都应被视为一个独特的管理单元（MU），用于保护目的，这与为其他国家（如哥伦比亚）确定的管理方式不同。
