Investigating phylogeographic structure of the oakgall wasp Andricus tomentosus in Turkey using CYT Bgene and ITS2 region sequences

Many species have evolved the ability to redirect plant growth and development to result a unique structure called galls, which provide gall inducing organisms with unique protection and food. Andricus tomentosus as an obligate parasitic gall wasp species forming its asexual generation galls in the section Quercus oaks were collected from 12 localities across Turkey. This thesis is designed to investigate and reveal genetic variation and its geographic distribution, population changes through expansion and contractions, divergence times between major lineages, as well as the possible reasons for the current distribution of genetic diversity. For these purposes, a 433 base pairs of mitochondrial DNA cytochrome b gene and the entire ITS2 region from nuclear genome were amplified and sequenced. All sequences generated 36 mtDNA haplotypes and 11 ITS2 alleles. Intermediate to high genetic variation was detected in A. tomentosus populations in Turkey. In addition, the higher diversity of haplotypes and lower diversity of nucleotide is an indication of population expansion. ML, MP, and Bayesian inference to reveal phylogenetic and phylogeographic structure of the species in Turkey also revealed that there is a geographical haplotype grouping. Application of molecular clock showed that the splitting of A. tomentosus from the outgroup species took place during the Miocene Epoch. Subsequent diversifications seem to have taken place within the species creating deep to intermediate to relatively shallow splits in A. tomentosus species in Turkey. The overall findings of this thesis revealed that factors such as paleoenvironmental changes and paleoclimatic oscillations have impacted their imprints on A. tomentosus in Turkey