334 Math & Natural Science Building, Department of Biology, Lincoln Memorial University, 6965 Cumberland Gap Parkway, Harrogate, Tennessee 37752 USA.
Am J Bot. 2013 Oct;100(10):2085-91. doi: 10.3732/ajb.1300038. Epub 2013 Oct 2.
The role of hybridization in plant evolution remains a source of intense debate. Potential consequences range from genetic dead-ends to species fusion or hybrid speciation. While much has been learned from model systems such as Populus, Iris, and Helianthus, many questions remain. Consisting of 11 species that are all capable of hybridizing, Sarracenia presents an excellent system in which to study hybridization. •
Using microsatellites, we examined a single field site consisting of three species: S. leucophylla, S. alata, and S. rubra subsp. wherryi. We determined the level of genetic admixture and compared it with allopatric sites of the same taxa. •
In contrast to the well-defined clusters formed when we examined the allopatric sites, the sympatric field site exhibited a wide range of admixture. Additionally, when the relative genetic makeup of "pure" species at the site was compared with the makeup of hybrids, we found that Sarracenia alata contributed disproportionately to the hybrid genomes. •
Our study provides further evidence that hybridization is contributing to interspecific gene flow in the genus and that all species do not contribute equally to hybridization. Implications for conservation are discussed.
杂交在植物进化中的作用仍然是激烈争论的来源。潜在的后果从遗传死胡同到物种融合或杂种形成不等。虽然从杨树、鸢尾和向日葵等模式系统中学到了很多，但仍有许多问题悬而未决。猪笼草由 11 个能够杂交的物种组成，是研究杂交的绝佳系统。
我们使用微卫星，研究了一个由三个物种组成的单一野外地点：白环猪笼草、马来王猪笼草和红猪笼草亚种。我们确定了遗传混合的程度，并将其与同分类单元的异域地点进行了比较。
与我们检查异域地点时形成的定义明确的聚类形成鲜明对比的是，同域野外地点表现出广泛的混合。此外，当比较该地点“纯”物种的相对基因组成与杂种的基因组成时，我们发现马来王猪笼草对杂种基因组的贡献不成比例。
我们的研究进一步证明，杂交正在促进该属种间基因流动，并且并非所有物种都平等地参与杂交。讨论了对保护的影响。
