An Investigation into the evolution of racial based diseases –Glioma using a drosophila model

Abstract

With cancer representing 13% of all deaths worldwide, it is the second biggest cause of death. Cancers of the brain despite being a rare cancer has shown increased occurrence rates of 39% in the last 40 years. This increased rate is due to difficulty in treating brain cancers.
Variation of the genome makes some individuals more susceptible to cancer than others. Brain tumors form familial mutations that are passed down to offspring, this is evidently seen throughout the human population and can be linked to an individual’s racial background. This research looked at a protein associated with glioma formation (merlin) and the inheritance of that protein to deduce whether cancer associated proteins follow Mendelian genetics or if epigenetics carries an important role. Merlin is encoded by the NF2 gene, and mutation causes the glioma predisposition, neurofibromatosis in humans. Merlin is seen homologous within both humans and Drosophila melanogaster (D. melanogaster) proving D. melanogaster to be a suitable model organism to study merlin. In this study three populations of D. melanogaster were bred, each with a distinct allele of merlin (Mer 3, Mer 4 and Wild-Type Mer), these alleles represented the variation within the human population; races. Populations were crossed to produce hybrid populations of the three variants of merlin. The mortality and survival rates were calculated and together with the expected phenotypic ratio showed that the drosophila were often surviving in higher rates than were expected and thus natural selection is suggested to be at work with the evolution of a population based on a gene for a cancerous phenotype.