Identification of genetic variants, by genome-wide association study, involved in the effects of a high sugar diet on locomotor activity in the presence of exerci̇se in Drosophila melanogaster

This thesis aims to identify genetic variants that determine the association between exercise and high sugar diet by Genome-Wide Association Analysis (GWAS). Many studies have shown that there is an interaction between exercise and diet. Especially in experiments conducted in wild-type flies, it is understood that exercise combined with sugar improves climbing performance. Although similar results were obtained in line with this finding, the opposite effect was also observed. This thesis is a comprehensive study to detect genetic differences between lineages within the same species with GWAS. Using 91 Drosophila Genetic Reference Panel (DGRP) lineages, climbing performance data was obtained by applying an exercise program in flies fed a high-sugar diet. Although an increase in climbing performance was observed in line with the literature in lines fed a high-sugar diet with an exercise program, there were also lines with a negative effect in the opposite direction. A total of 8 GWASs were conducted from the data obtained as a result of the experiments. However, the GWASs conducted with the average data from individuals who exercised and were fed a high sugar diet, the average difference data from individuals who were fed a high sugar diet and exercised and did not exercise, and the average difference data from individuals who were fed a high sugar diet and were fed a standard diet and exercised were the most important GWASs in terms of examining the relationship between exercise and high sugar diet. A total of 407 variants were identified from the 8 GWASs, while 153 variants were identified in the 3 GWASs mentioned, and 113 had human orthologs. These variants are related to the skeletal-muscular system, cellular regulatory pathways, development, and metabolism, which are known to be related to exercise and high-sugar diet. Gene ontology analysis using the orthologous genes revealed several diseases associated with a high-sugar diet. As a result of this thesis, is planned to identify the genetic variants behind the relationship between exercise and high sugar diet and to contribute to the literature.