Molecular phylogenetics of Turkish Salix L. species

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Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Biyolojik Bilimler Bölümü, Türkiye

Tezin Onay Tarihi: 2017

Öğrenci: PELİN ACAR

Danışman: ZEKİ KAYA

Özet:

Chloroplast (trnT-F, matK and rbcL) and nuclear genome (ITS) regions were used to explore the evolutionary relationships of Salix species which are native to Turkey. Morphological analysis with the utilization of Principal Component Analysis (PCA) was also carried out. Such a combined sequence data from cpDNA and nrDNA genes enabled reliable subgenus-level classification of Turkish willows (subgenus Salix and Vetrix). Morphological and genetic results agree with traditional taxonomic concepts in clustering of two subgenera. Two coding cpDNA gene regions (matK and rbcL) are found as conserved whereas non-coding cpDNA (trn T-F) and nrDNA (ITS) evolved rapidly for Turkish Salix. Turkish willow species appear to be a monophyletic (cpDNA) or potentially monophyletic (nrDNA) with having two well supported clades. Biogeographically, subg. Vetrix species are located in high altitude and cool climate whereas subg. Salix species are in warmer climate. S. acmophylla is always located at distant positions of subg. Salix clade. The appearance of the subg. Vetrix members (S. rizeensis and S. amplexicaulis) in subg. Salix clade can be explained by occurrence of natural hybrids with species from subg. Salix in shared habitat. New World (America) and Old World (Asia) Salix species are scattered throughout Turkish subgenera in all phylogenetic trees. The close molecular relations between subg. Salix-OWS and subg. Vetrix-NWS were determined by taxonomical relations, rather than geographical distribution. Turkish subgenera were diverged from others in late Pliocene. Chloroplast introgression and incomplete lineage sorting events in Salix species of Turkey may explained the high haplotype diversity in the genus.