Institut de Recherche en Biologie Végétale, Université de Montréal, 4101 Sherbrooke est, Montréal, Québec H1X 2B2 Canada;
Am J Bot. 2006 Mar;93(3):412-25. doi: 10.3732/ajb.93.3.412.
This study investigates the impact of hybridization and polyploidy in the evolution of eastern North American roses. We explore these processes in the Rosa carolina complex (section Cinnamomeae), which consists of five diploid and three tetraploid species. To clarify the status and origins of polyploids, a haplotype network (statistical parsimony) of the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) nuclear gene was estimated for polyploids of the complex and for diploids of section Cinnamomeae in North America. A genealogical approach helped to decipher the evolutionary history of polyploids from noise created by hybridization, incomplete lineage sorting, and allelic segregation. At the diploid level, species west of the Rocky Mountains are distinct from eastern species. In the east, two groups of diploids were found: one consists of R. blanda and R. woodsii and the other of R. foliolosa, R. nitida, and R. palustris. Only eastern diploids are involved in the origins of the polyploids. Rosa arkansana is derived from the blanda-woodsii group, R. virginiana originated from the foliolosa-nitida-palustris group, and R. carolina is derived from a hybrid between the two diploid groups. The distinct origins of these polyploid taxa support the hypothesis that the three polyploids are separate species.
本研究探讨了杂交和多倍体在北美东部玫瑰进化中的作用。我们研究了由五个二倍体和三个四倍体物种组成的罗莎·卡罗莱纳复合体（桂皮亚组）中的这些过程。为了阐明多倍体的地位和起源，我们对复合体的多倍体和北美的桂皮亚组的二倍体的甘油醛 3-磷酸脱氢酶（GAPDH）核基因的单倍型网络（统计简约）进行了估计。系统发育方法有助于从杂交、不完全谱系分选和等位基因分离产生的噪声中破译多倍体的进化历史。在二倍体水平上，落矶山脉以西的物种与东部物种明显不同。在东部，发现了两组二倍体：一组由 R. blanda 和 R. woodsii 组成，另一组由 R. foliolosa、R. nitida 和 R. palustris 组成。只有东部的二倍体参与了多倍体的起源。罗莎·阿肯色州起源于 blanda-woodsii 组，R. virginiana 起源于 foliolosa-nitida-palustris 组，而 R. carolina 起源于这两个二倍体组之间的杂交。这些多倍体类群的明显起源支持这样的假设，即这三个多倍体是独立的物种。
