新生代印度和亚洲板块的撞击事件可以说是目前地球上最大和最积极的造山运动,在亚洲由此引发了一系列重要的地质地壳运动和气候变化,重新塑造着新生代的亚洲大陆板块,如青藏高原的抬升、东南亚地区(主要为马来半岛)的侧向逃逸、以及亚洲季风气候的盛行等。对于这样一个全球一级板块区域,和地质学家一样,生物学家也同样有着浓厚的研究兴趣。喜马拉雅地区,中国西部山脉,缅甸-马来半岛区域等三个全球生物多样性热点区历来是生物学家们研究物种起源、分化的天然实验室。
在昆明动物所张亚平院士研究组与加州大学伯克利分校脊椎动物博物馆的David B. Wake院士研究组的合作中,车静副研究员等对亚洲特有分布的两栖类群–棘蛙族进行了系统进化和详细的生物地理分析。棘蛙族物种在亚洲沿喜马拉雅山分布,从巴基斯坦,印度东部,缅甸进入马来半岛地区,向北进入中国南方广大地区,同时在青藏高原也有分布。在中国,棘蛙又俗称“石蛙”,大部分棘蛙物种生活在深山,多石,急流处,其特殊的生存环境需求和雄性第二性征及其在亚洲重要的分布区域使其成为研究物种性状进化以及生物地理的绝好材料。结合棘蛙族的分子进化历史,分子钟估算,以及生物地理分析,该研究提出:在渐新世早期,亚洲开始出现明显的地理和气候的转型,一直延续到中新世呈现加强趋势,环境的变化无疑造成了棘蛙族物种的快速分化。隔离是造成西部高海拔物种分化的主要原因,而对于低海拔物种,明显地,分布在中国南方的物种来自马来半岛物种的一次重要的扩散事件。另外该结果第一次从分子生物学的角度上支持了地质学假说:由于印度板块和亚洲板块的撞击,青藏高原和喜马拉雅不同的地区先后发生了隆起事件,其中在渐新世和中新世转型期间,一次隆起事件和马来半岛的侧向逃逸事件几乎是同时发生的。
著名地质学家An Yin评价“The work presented by Che et al. is the first large-scale paleogeographic reconstruction of the Indo-Asian collision zone using a biological approach. This is an important start and I expect more work along the same line to emerge in the coming decades”. PNAS编辑委员会评价:I judge this contribution as one of the best of its kind in the field linking DNA based phylogeny with plate tectonics. Details will be debated but it sets a wonderful base for future investigations throughout the world.
本研究得到了科技部国家重点基础研究发展计划(973)以及美国国家自然科学基金的支持。另外车静获2008年度中国科学院公派出国留学计划“访问学者”项目资助赴美开展亚洲两栖类合作研究。
原文出处:
PNAS doi: 10.1073/pnas.1008415107
Spiny frogs (Paini) illuminate the history of the Himalayan region and Southeast Asia
Jing Che a , b , Wei-Wei Zhou a , Jian-Sheng Hu a , c , Fang Yan a , Theodore J. Papenfuss b , David B. Wake b , 1 , and Ya-Ping Zhang a , d , 1
aState Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, People's Republic of China;
bDepartment of Integrative Biology, Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720; and
cCollege of Life Sciences and
dLaboratory for Conservation and Utilization of Bioresources, Yunnan University, Kunming 650091, People's Republic of China
Asian frogs of the tribe Paini (Anura: Dicroglossidae) range across several first-order tectono-morphological domains of the Cenozoic Indo-Asian collision that include the Tibetan Plateau, the Himalayas, and Indochina. We show how the tectonic events induced by the Indo-Asian collision affected the regional biota and, in turn, how the geological history of the earth can be viewed from a biological perspective. Our analysis of a concatenated dataset comprising four nuclear gene sequences of Paini revealed two main radiations, corresponding to the genera Nanorana (I) and Quasipaa (II). Five distinct clades are recognized: Tibetan plateau clade (I-1), Himalaya clade (I-2), environs of Himalaya–Tibetan plateau clade (I-3), South China clade (II-1), and Indochina clade (II-2). This pattern of relationships highlights the significance of geography in shaping evolutionary history. Building on our molecular dating, ancestral region reconstruction, and distributional patterns, we hypothesize a distinct geographic and climatic transition in Asia beginning in the Oligocene and intensifying in the Miocene; this stimulated rapid diversification of Paini. Vicariance explains species formation among major lineages within Nanorana. Dispersal, in contrast, plays an important role among Quasipaa, with the southern Chinese taxa originating from Indochina. Our results support the tectonic hypothesis that an uplift in the Himalaya–Tibetan plateau region resulting from crustal thickening and lateral extrusion of Indochina occurred synchronously during the transition between Oligocene and Miocene in reaction to the Indo-Asian collision. The phylogenetic history of Paini illuminates critical aspects of the timing of geological events responsible for the current geography of Southeast Asia.