Abstract
The Qinghai-Tibetan Plateau (QTP) represents one of the earth’s most significant physical features and there is increasing interest in the historical generation of biodiversity within this region. We hypothesized that there should be clear geographically coherent genetic structuring within one of the world’s highest altitude lizards, Phrynocephalus theobaldi, due to considerable historical population fragmentation in this environment. This was tested using a major mitochondrial DNA (mtDNA) survey and sequencing of two nuclear markers (AME and RAG-1) from P. theobaldi, from across the southern QTP. A Bayesian method (BPEC) was used to detect four geographically structured mtDNA clusters. A Bayesian phylogenetic tree, together with associated dating analyses, supported four corresponding evolutionary lineages with a timing of 3.74–7.03 Ma for the most basal P. theobaldi split and Pliocene splits of 2.97–5.79 Ma and 2.40–5.39 Ma in the two daughter lineages. Himalayan uplift and changes in the Jilong basin may have contributed to these divergences, but uplift of the Gangdese mountains is rejected due to its timing. The nuclear markers appeared to be sorted between the four mtDNA groups, and species delimitation analyses supported the four phylogeographical groups as candidate species. The study contributes to our understanding of biodiversity on the QTP.
Highlights
Many of these studies have associated Qinghai-Tibetan Plateau (QTP) uplift with recent diversification, but this has been questioned based on the premise that the plateau reached its present height at least 15 million years (Ma) ago and probably much earlier, during the Eocene[13]
Detailed information on mitochondrial DNA (mtDNA) haplotype and nuclear genotype sequences, and their correspondence with individuals and with the sample sites shown in Fig. 1 are provided in the Supplementary information (S1 and S2)
Deep and relatively ancient geographically structured divergence was detected within P. theobaldi, which was concordant between nuclear and mtDNA markers
Summary
Many of these studies have associated QTP uplift with recent diversification, but this has been questioned based on the premise that the plateau reached its present height at least 15 Ma ago and probably much earlier, during the Eocene[13]. We hypothesized that if population fragmentation was caused by physical events (such as orogenic uplift) major geographical structuring would correspond to the relevant geological features, as would timings of intraspecific divergence. We tested this hypothesis by means of a major mtDNA survey, identification of phylogeographic clusters, divergence time dating of these clusters, and analyses of nuclear DNA sequences to investigate concordance of patterns between different loci, which provides insights into whether clusters might represent valid species ( this study does not aim to describe new taxonomic units)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
