ABSTRACT

Although guanacos (Lama guanicoe) are widely distributed throughout much of their historic range, they are often restricted to small, isolated populations that are at risk of inbreeding and loss of genetic diversity. Here we document and interpret baseline patterns of genetic variation in a guanaco population inhabiting in the Bolivian Chaco that is threatened by hunting and habitat degradation. The region, once open grasslands, is dominated by dense shrubs, the result of livestock grazing. The most-recent census identified only 74 individuals and is designated as at ‘risk of extinction’ by the Bolivian government. We assessed the population’s genetic health and uniqueness from the genetic patterns of 16 microsatellite loci, the Hyper-variable Domain I of the mitochondrial Control Region and SRY gene with 29 fecal samples. We identified 19 male and 10 female unique individuals. Microsatellite variation (Ho = 0.64) was similar to larger, less-isolated populations. However, the estimated effective population size was low and consistent with the continuing loss of allelic variation. The two observed mtDNA haplotypes are common in other L. g. guanicoe populations. Although we documented moderate genetic diversity, gene flow among Bolivian and Paraguayan guanaco Chaco populations should be assessed and integrated into explicit conservation management plans.

摘要

虽然原驼 ( Lama guanicoe) 广泛分布于其历史范围内的大部分地区，但它们通常仅限于存在近亲繁殖和遗传多样性丧失风险的小型孤立种群。在这里，我们记录并解释了居住在受狩猎和栖息地退化威胁的玻利维亚查科原驼种群遗传变异的基线模式。该地区曾经是开阔的草原，现在主要是茂密的灌木丛，这是牲畜放牧的结果。最近的人口普查仅确定了 74 个人，并被玻利维亚政府指定为“濒临灭绝”。我们从 16 个微卫星位点的遗传模式、线粒体控制区的超变域 I 和 29 个粪便样本的 SRY 基因评估了人群的遗传健康和独特性。我们确定了 19 名男性和 10 名女性的独特个体。微卫星变异 (Ho = 0.64) 与较大、较少孤立的种群相似。然而，估计的有效种群规模很低，并且与等位基因变异的持续丢失一致。观察到的两种 mtDNA 单倍型在其他L.g. guanicoe种群。尽管我们记录了适度的遗传多样性，但玻利维亚和巴拉圭原驼 Chaco 种群之间的基因流动应该被评估并纳入明确的保护管理计划。