Biogeography, population genomics and numerical taxonomy of alpine Phyllolepidum cyclocarpum (Boiss.) L. cecchi subsp. cyclocarpum

This study aimed to determine the relationships between the eastern and western population groups of Phyllolepidum cyclocarpum subsp. cyclocarpum, a taxon endemic to Turkey found in the alpine rocks of the Taurus and Anatolian Diagonal mountains (Taurus Way). Using RADSeq data and genome-level sampling, the study sought to uncover the species' demographic structure. Field studies were conducted in the Taurus Way mountains, targeting localities and potential habitats identified through literature review. For morphological analysis, only quantitatively measurable characters were considered, and the data set was evaluated via Principal Component Analysis. Additionally, 140 individuals from 15 populations were sequenced using the RADSeq method. Genomic data analysis utilized both Single Nucleotide Polymorphism (SNP) and loci obtained using snakeRAD. Phylogenetic analyses employed both parsimony-informative 50 loci and three randomly sampled 50 loci datasets. Coalescent-based and time-calibrated phylogenomic analyses with locus data, along with PCA and admixture analyses with SNP data, demonstrated clear differentiation between eastern and western population groups. Genomic findings were supported by morphological data. The study also revealed high genetic differentiation within eastern populations and low genetic diversity within western populations, with significant differentiation between the two groups. Demographic analyses indicated a significant population construction in both eastern and western populations following the Last Glacial Maximum and early Dryas Period glaciations, respectively.