Phylogenetics of the florally diverse Andean clade Iochrominae (Solanaceae)
Phylogenetics of the florally diverse Andean clade Iochrominae (Solanaceae)
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DOI：
10.3732/ajb.93.8.1140
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发表时间：
2006-08-01
影响因子：
3
通讯作者：
Baum, David A.
中科院分区：
文献类型：
--
作者：
Smith, Stacey DeWitt;Baum, David A.
最近对茄科的分子系统发育研究已经确定了该科中许多得到充分支持的分支，并允许创建一个分类的系统发育系统。在这里，我们估计了Iochrominae的系统发育，Iochrominae是Physaleae sensu Olmstead et al.（1999）的一个分支，它包含34个安第斯物种，涵盖了巨大的花朵形式和颜色的多样性。利用ITS、LEAFY基因的第二个内含子和淀粉合成酶基因（waxy）的2 ~ 9外显子三个核区，我们评估了包含碘铬属的传统属的单一性，并评估了该分支内种间杂交的程度。在传统认识的六属中，只有一属被认为是单系的。此外，个体核数据集的比较揭示了两个种间杂交分类群和第三个可能的案例。这些杂交分类群出现在安第斯山脉北部和中部之间的Amotape-Huancabamba地区，该地区具有最大的Iochroma物种多样性，并且在同属区提供了频繁的杂交机会。我们推测，该地区的周期性杂交事件，加上传粉媒介的选择和潜在的微异源性，可能共同促进了山地安第斯分类群的多样化，如Iochrominae。
Recent molecular phylogenetic studies of Solanaceae have identified many well-supported clades within the family and have permitted the creation of a phylogenetic system of classification. Here we estimate the phylogeny for Iochrominae, a clade of Physaleae sensu Olmstead et al. (1999), which contains 34 Andean species encompassing an immense diversity of floral forms and colors. Using three nuclear regions, ITS, the second intron of LEAFY, and exons 2 to 9 of the granule-bound starch synthase gene (waxy), we evaluated the monophyly of the traditional genera comprising Iochrominae and assessed the extent of interspecific hybridization within the clade. Only one of the six traditionally recognized genera of Iochrominae was supported as monophyletic. Further, comparison of the individual nuclear data sets revealed two interspecific hybrid taxa and a third possible case. These hybrid taxa occur in the Amotape-Huancabamba zone, a region between the northern and central Andes that has the greatest diversity of Iochroma species and offers frequent opportunities for hybridization in areas of sympatry. We postulate that periodic hybridization events in this area coupled with pollinator-mediated selection and the potential for microallopatry may have acted together to promote diversification in montane Andean taxa, such as Iochrominae.