A new look at the genus Crocus L. phylogeny and speciation: Insight from molecular data and chromosome geography

The genus Crocus of the family Iridaceae is a monophyletic genus with over 100 species. Due to the high degree of hybridization and the changes in the number of chromosomes known to have occurred in the genus Crocus, it is important to investigate the biogeography of the genus Crocus. Many studies revealed that ITS and chloroplast genes produce somewhat incongruent phylogenetic.trees with regard to Crocus species phylogeny, and therefore, it is better to use combined molecular data for contracting such a tree. Thus, we used both molecular and cytological sets to construct the phylogenetic tree. We conducted the present study to investigate potential use of some plastid genes as well as ITS sequences to illustrate the divergence of species. We also aimed to identify molecular events like horizontal gene transfer (HGT) and deep coalescence that may be associated with geographical distribution of Crocus taxa to present more illustratively the chromosome changes during Crocus taxa diversification. Reports on the genus Crocus that multiple polyploidization events as well as frequently-occurring diploid are major cytological events in Crocus taxa diversification. The present study showed close genetic affinity between three species of C. sativus, C. pallasii and C. cartwrightianus; and BEAST chronological tree showed that C. sativus diverged from these species in Turkey-Greece the region around 1-2 MY ago. In conclusion we may say that HGT, deep coalescence, gene duplication and deletion and perhaps barcode specification are among the molecular events which played role in the species diversification of the genus Crocus L. We could also present DNA barcodes for a few important Crocus distribution areas for the first time.