Fruit flies unlock Methuselah’s secrets

New research published in Genome Biology investigates genes that increase the life span of fruit flies in an effort to gain a greater understanding of the ageing process. The researchers from the University of Southern California and Harvard Medical School screened 10,000 fruit fly populations that were mutated.

Their results revealed that six populations of mutant flies lived 5-17% longer than normal. Furthermore, analysis of these long-lived flies showed that the extended life span was caused by the overexpression of six different genes.

The use of the fruit fly Drosophila melanogaster in aging research is common as these flies are short-lived in comparison to humans but carry out many of the same biological processes. The current focus of research is on genes that increase the life span of an animal because it is difficult to disentangle changes that decrease life span from those that cause disease.

Jumping genes or transposable elements are regions of DNA that are able to move around the genome of an organism. The movement of these transposable elements can cause mutations because they interrupt a gene in another part of the genome. Gary Landis, Depak Bhole and John Tower exploited this phenomenon by using a chemically controlled transposable element that acts as an accelerator of gene expression to find mutations that could make flies live longer. Crucially, they were able to turn this acceleration on an off by feeding the flies a specific chemical and to look at the effects of the mutations in adult flies.

Their experiments revealed six fly populations that lived 5-17% longer than normal flies. Characterisation of these mutant flies showed increased expression of a different gene for each population. Interestingly the overexpressed genes were involved in a variety of fundamental cellular processes, which raises the possibility that similar effects are produced in higher organisms or even humans. The authors, however, are cautious about the implications of their findings

“Further experiments will be required to confirm the role of these genes in life-span regulation, and to determine their interactions with each other and in known or novel life-span regulatory pathways.”