Ancient vicariance and climate‐driven extinction explain continental‐wide disjunctions in Africa: the case of the Rand Flora genus Canarina (Campanulaceae)
Ancient vicariance and climate‐driven extinction explain continental‐wide disjunctions in Africa: the case of the Rand Flora genus Canarina (Campanulaceae)
复制标题
古代变异和气候驱动的灭绝解释了非洲大陆范围内的分离：以兰德植物群Canarina（桔梗科）属为例
作者：
M. Mairal;Lisa Pokorny;J. Aldasoro;M. L. Alarcón;I. Sanmartín
几个世纪以来，跨洋分布一直吸引着科学家的兴趣。很少有人注意到“大陆范围”分离的进化起源，其中相关的分类群分布在同一大陆内的孤立地区。一个最好的例子是“兰德植物群”模式，它表明姐妹分类群间断地分布在非洲大陆边缘。在这里，我们探索这种模式的进化起源使用属Canarina，有三个物种：C。canariensis和C. eminii和C. Abyssinica，东非非洲山区特有的，作为案例研究。我们推断系统发育关系，分歧的时间和历史的移民事件在卡纳林纳使用贝叶斯推断的大样本的叶绿体和核序列。利用生态位模拟方法，对Canarina的气候生态位进行了时间推断。使用一种新的嵌套方法进行测年，以解决在包括以上物种和群体水平采样的分子数据集中使用深时间校准点的问题。结果表明C. abyssinica是由间断C. eminii和C.加那利群岛。中新世分歧推断物种之间，而种下分歧属于更新世-全新世时期。虽然C. eminii和C. canariensis表现出较强的遗传地理结构，前者的种群间分化比后者早。我们的研究结果表明，Canarina起源于东非，后来迁移到北非，与vicariance和干旱化驱动的灭绝解释了7000公里/700万年的加那利群岛和东非地方病之间的分歧。
Transoceanic distributions have attracted the interest of scientists for centuries. Less attention has been paid to the evolutionary origins of ‘continent‐wide’ disjunctions, in which related taxa are distributed across isolated regions within the same continent. A prime example is the ‘Rand Flora’ pattern, which shows sister taxa disjunctly distributed in the continental margins of Africa. Here, we explore the evolutionary origins of this pattern using the genus Canarina, with three species: C. canariensis, associated with the Canarian laurisilva, and C. eminii and C. abyssinica, endemic to the Afromontane region in East Africa, as case study. We infer phylogenetic relationships, divergence times and the history of migration events within Canarina using Bayesian inference on a large sample of chloroplast and nuclear sequences. Ecological niche modelling was employed to infer the climatic niche of Canarina through time. Dating was performed with a novel nested approach to solve the problem of using deep time calibration points within a molecular dataset comprising both above‐species and population‐level sampling. Results show C. abyssinica as sister to a clade formed by disjunct C. eminii and C. canariensis. Miocene divergences were inferred among species, whereas infraspecific divergences fell within the Pleistocene–Holocene periods. Although C. eminii and C. canariensis showed a strong genetic geographic structure, among‐population divergences were older in the former than in the latter. Our results suggest that Canarina originated in East Africa and later migrated across North Africa, with vicariance and aridification‐driven extinction explaining the 7000 km/7 million year divergence between the Canarian and East African endemics.
DOI：
10.1073/pnas.84.24.9054
发表时间：
1987-12-01
影响因子：
11.1
作者：
WOLFE, KH;LI, WH;SHARP, PM
通讯作者：
SHARP, PM
影响因子：
10.7
作者：
Baele, Guy;Lemey, Philippe;Alekseyenko, Alexander V.
通讯作者：
Alekseyenko, Alexander V.
影响因子：
2.7
作者：
Gehrke, Berit;Linder, H. P.
通讯作者：
Linder, H. P.