Cyprininae phylogeny revealed independent origins of the Tibetan Plateau endemic polyploid cyprinids and their diversifications related to the Neogene uplift of the plateau.

Xuzhen Wang,Shunping He,Xiaoni Gan,Junbing Li,Yiyu Chen

doi:10.1007/s11427-016-0007-7

Xuzhen Wang, Shunping He + Show 3 more

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https://doi.org/10.1007/s11427-016-0007-7

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Abstract

Origin and diversification of the Tibetan polyploid cyprinids (schizothoracins) may help us to explore relationships between diversification of the cyprinids and the Tibetan Plateau uplift. Cyprininae phylogeny was analyzed using mitochondrial and nuclear DNA sequences to trace origins of polyploidy and diversifications of schizothoracins. Ancestral states reconstruction for ploidy levels indicated that the Cyprininae was diploid origin and the schizothoracin clades tetraploid origins. There were two diversification rate shifts along with diversification of the cyprinine fishes in response to the Tibetan uplift. The unusual diversification shifts were located to branches subtending the clades of Tibetan polyploid cyprinids. Our analyses suggested that (i) phylogeny of Cyprininae recovered two independent origins of the Tibetan polyploidy schizothoracins; (ii) diversifications of the schizothoracins were closely related to the Neogene uplift of the Tibetan plateau in the following ways: the relatively ancient Late Oligocene-Middle Miocene adaptive radiation may be associated with the uplift of the southern Tibet and Himalaya; the Middle Miocene-Early Pleistocene lineage-specific diversification broadly coincident with major phase of the Neogene Tibetan uplift; and the most recent Pleistocene diversification shift in Schizothorax closely coincident with the successive Kunlun-Huanghe and Gonghe movements of the Tibetan uplift and the glaciation-induced climate oscillations on the plateau.

Highlights

The Tibetan Plateau, known as the Qinghai-Tibetan Plateau, is the biggest and highest plateau with an area of 2.5 million square kilometers and an average elevation of over 4,500 m
The aims of this study are (i) to provide the well resolved phylogeny of Cyprininae to understand the relationships among the polyploidy schizothoracins; (ii) to provide insights into the dates of cladogenetic events leading to origins and diversifications of the polyploid species within the subfamily Cyprininae; (iii) to determine whether the late Cenozoic uplift of the Tibetan Plateau has significantly affected the diversification of the plateau polyploid cyprinids by estimating patterns of diversification within the subfamily Cyprininae (Figure 1)
The monophyly of labeonine fishes was strongly corroborated with high bootstrap support (≥94%) and posterior probability (1.0), and the monophyly of the remaining cyprinine fishes was supported with a posterior probability of 0.94 in the Bayesian analysis and a relatively moderate bootstrap proportion of 77% and 58% in the maximum likelihood (ML) and maximum parsimony (MP) analyses, respectively

Summary

Introduction

The Tibetan Plateau, known as the Qinghai-Tibetan Plateau, is the biggest and highest plateau with an area of 2.5 million square kilometers and an average elevation of over 4,500 m. The extreme environmental conditions characteristic of the Tibetan Plateau include high absolute elevation, low temperature, and hypoxia. Polyploidy in plants of the Tibetan Plateau is expected to occur at a high rate because of the tremendous species diversity of polyploidy endemic to the Plateau and the extensive habitats for alpine plants in the Plateau (Liu, 2004; Nie et al, 2005; Tang et al, 2005; Zhang et al, 2009), indicating that polyploidy is a common and successful evolutionary transition under the most extreme environmental conditions of the Tibetan Plateau. The extensive occurrence of polyploidy was found in some groups of cyprinid fishes (Leggatt and Iwama, 2003; Yu et al, 1987, 1989), most of which were characteristic of the Tibetan Plateau and its adjacent regions (Yue, 2000). It is well known that cyprinid fishes endemic to the Tibetan Plateau and its adjacent regions are major vertebrates in which polyploidy can be commonly. X., et al Sci China Life Sci November (2016) Vol. No.11 observed and expected, less attention has focused on origin and evolution of these polyploid cyprinids related to the Tibetan Plateau

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