Contrasting evolutionary origins of two mountain endemics: Saxifraga wahlenbergii (Western Carpathians) and S. styriaca (Eastern Alps).

Affiliation

Institute of Biology, Martin Luther University Halle-Wittenberg, Neuwerk 21, 06108, Halle, Germany. [Email]

Abstract

The Carpathians and the Alps are the largest mountain ranges of the European Alpine System and important centres of endemism. Among the distinctive endemic species of this area is Saxifraga wahlenbergii, a Western Carpathians member of the speciose genus Saxifraga. It was frequently considered a taxonomically isolated Tertiary palaeopolyploid and palaeoendemic, for which the closest relatives could not yet be traced. A recently described narrow endemic of the Eastern Alps, S. styriaca, was hypothesized to be closely related to S. wahlenbergii based on shared presence of peculiar glandular hairs. To elucidate the origin and phylogenetic relationships of both species we studied nuclear and plastid DNA markers based on multiple accessions and analysed the data in a wide taxonomic context. We applied Sanger sequencing, followed by targeted next-generation sequencing (NGS) for a refined analysis of nrITS variants to detect signatures of ancient hybridization. The ITS data were used to estimate divergence times of different lineages using a relaxed molecular clock.

Keywords

Alps,Carpathians,Endemics,European mountains,Hybrid speciation,ITS genomic screening,Molecular clock,NGS,Phylogenetics,Tertiary relict,