Australasian Microarray & Associated Technologies Association, AMATA

Morgan, SM, Dearden, PK and Raubeheimer, D
Biochemistry, University of Otago, 710 Cumberland Street, Dunedin, Otago 9054, New Zealand

The life history trade off between longevity and reproduction is seen in a variety of animals. Organisms able to produce a large amount of offspring in a short amount of time invariably have a shorter lifespan than their reproductively frugal counterparts. This has been taken a step further with the model organism Drosophila melanogaster in that regulation of lifespan and reproduction rates have been linked with various ratios of protein to carbohydrate diet ingested by the flies throughout their lifetime.

Dietary Restriction and its effects on lifespan have been studied for many years, with consistent results seen between vastly different organisms. Restriction of caloric intake is known to extend lifespan in these different organisms. Initially called Caloric Restriction, it has been shown in Drosophila that isocaloric diets of yeast (as a protein source) and sugar, in varying ratios, results in organisms portraying the typical trade-off between lifespan and reproduction implying that it is macronutrient status rather than caloric restriction that is extending lifespan. Isocaloric is the term used to describe diets of differing component ratios, while maintaining the same calorie value. When given the option, Drosophila are able to self regulate diet intake and maximise lifetime reproduction.

The aim of the current study is to determine the patterns of gene expression associated with longevity and reproduction in fruit fly. The Drosophila are fed varying ratios of a protein/carbohydrate diet, whole fly RNA will be extracted and gene expression will be assayed via Affymetrix microarrays, and differentially expressed genes will be verified with qRT-PCR. Once candidate genes have been identified, mutation studies will be used to further validate the results and identify pathways that control the trade-offs between reproduction and longevity.