Gaskin John F, Zhang Dao-Yuan, Bon Marie-Claude
Northern Plains Agricultural Research Laboratory, USDA-ARS, P.O. Box 463, Sidney, MT 59270 USA.
Mol Ecol. 2005 Jul;14(8):2331-41. doi: 10.1111/j.1365-294X.2005.02589.x.
Advances in phylogeography are of great value for understanding the population structure and origins of invasive genotypes. Such insights provide constructive information for current or future biological control research efforts. In this study, we investigated a highly variable chloroplast DNA (cpDNA) marker for populations of the weed Lepidium draba (Brassicaceae) in its native Eurasian and invasive US ranges. We sequenced DNA from 684 individuals from Eurasia and the US and found 41 different haplotypes. Our comparative study between the native and invasive ranges showed a 33% reduction in allelic richness (A) and a 7% reduction in haplotype diversity (h) since introduction into the US. Most genetic variation in the native range was observed within geographical regions and populations, not between regions, and this result was similar for the invasive range. Assignment tests indicated the most likely origins of many invasive haplotypes. Some of these occurred in western Europe, supporting an expanded native range that had been proposed for the species. Exact locations were identified for a diverse set of invasive haplotypes which can be used in ongoing host-specificity tests of potential biological control agents.
系统发育地理学的进展对于理解入侵基因型的种群结构和起源具有重要价值。这些见解为当前或未来的生物防治研究工作提供了建设性信息。在本研究中，我们针对杂草北美独行菜（十字花科）在其原生欧亚大陆和入侵的美国分布范围内的种群，研究了一种高度可变的叶绿体DNA（cpDNA）标记。我们对来自欧亚大陆和美国的684个个体的DNA进行了测序，发现了41种不同的单倍型。我们对原生范围和入侵范围的比较研究表明，自引入美国以来，等位基因丰富度（A）降低了33%，单倍型多样性（h）降低了7%。在原生范围内，大多数遗传变异是在地理区域和种群内部观察到的，而不是在区域之间，入侵范围的情况也类似。归巢测试表明了许多入侵单倍型最可能的起源。其中一些出现在西欧，支持了该物种曾被提议的扩大的原生范围。确定了一组不同入侵单倍型的具体位置，可用于正在进行的潜在生物防治剂宿主特异性测试。
