The Evaluations and Comparisons of Nuclear and Chloroplast DNA Regions Based on Species Identification and Phylogenetic Relationships of Crocus L. Taxa

Abstract

The genus Crocus L. (Iridaceae) consists of about 200 species distributed from western Europe and north west Africa to western China. The genus is taxonomically very problematic and day after day it becomes more difficult to understand the relationships between Crocus species because of the identification of new species. Recently, the studies based on DNA sequences are frequently used for the solution of taxonomic problems, the determination of species diversity and especially the evaluation of phylogenetic relationships among the studied taxa. The use of the regions belonging to nuclear DNA and especially chloroplast genome and the combinations of these regions are frequently recommended in many studies. However, there is no information about suitable barcoding regions that can be used for all plant groups. This study focuses on determination of the most succesful barcoding regions, understanding the species discrimination abilities and finally evaluation of phylogenetic relationships among the Crocus taxa using one region from nuclear DNA (ITS1-5.8S rRNA gene-ITS2) and four regions from chloroplast DNA (1. trnK-matK IGS, 2. partial psbA gene-psbA/trnH IGS-partial trnH gene, 3. rpoC1 gene, 4. partial trnL gene-trnL/trnF IGS-partial trnF gene). Sequence informations for related DNA regions were obtained from NCBI. As a result, it can be stated that the region which is only covering ITS1-5.8S rRNA gene-ITS2 separated the all taxa in species level and it is more beneficial for the phylogenetically evaluation of Crocus taxa. Furthermore, dendrogram show taxonomic problems belonging to some species in the genus such as C. biflorus taxa.