Karyotypes of 10 Anuran Species from the Qinghai–Tibetan Plateau

Abstract

The Qinghai–Tibet Plateau (QTP) is the highest and largest mountain plateau in the world, which has become a focus area of amphibian biodiversity research and conservation, depending on its large number of endemic and threatened species. Among the 58 families of Anura, only a few species of four families (Megophryidae, Bufonidae, Dicroglossidae, Ranidae) are distributed in QTP. Revealing the genetic diversity of these species is crucial for research on their environmental adaptability and biodiversity conservation. Chromosome rearrangements are a critical source of genetic variation, which is recognized as a driver of speciation, providing the genetic material for differentiation and environmental adaptation of amphibians. Here, we identified the karyotypes of 10 species of the above families from the QTP. The karyotypes of these species were obtained from new sites that were not previously reported. Among them, the karyotypes of D. himalayanus and tetraploid B. zamdaensis were reported for the first time. In particular, the ploidy of B. zamdaensis from Zanda, China, was found to be distinctly different from the ploidy from Spiti River, India. This indicates that they have presented species differentiation and supports the multiple and complicated polyploidization events in the Bufotes toads. Furthermore, the different locations of the secondary constriction between the Weixi and Zhongdian populations of O. xiangchengensis support that there is a karyotypic variation between the two subspecies (O. xiangchengensis xiangchengensis vs. O. xiangchengensis deqinicus). A series of chromosomal variations may have facilitated the rapid evolution of amphibians in the QTP, and our study will provide support for further research on amphibian genetic diversity and biodiversity conservation.