Human, Fruit Fly Weight Controlled By Similar Genes

Fruit fly genetics have been of great use in shedding light on human characteristics such as embryology. The degree is startling, since scientific evidence indicates the last common ancestor of humans and fruit flies lived hundreds of millions of years ago.

The similarity extends to genes governing weight and could provide new targets for obesity drugs, according to a paper recently published in BioMed Central Genetics .

The researchers studied genes variants that influence storage of triacylglycerol, or TAG in Drosophila melanogaster, the common fruit fly. In humans, high blood levels of these chemicals -- more commonly known as triglycerides -- are associated with obesity. The researchers found that in fruit flies, a mutant version of a gene called LanA, when homozygous, or inherited from each parent, had significantly lower storage of TAG and body weight.

The Drosophila LanA gene is closely related to a human gene called LAMA5, which is present in a section of a human chromosome connected with obesity. The researchers found that variants of that gene were linked to weight, fat and HDL cholesterol.

Looking at the similarities in the gene variants' role in determining weight and body composition in humans and fruit flies, the researchers say it appears this function is evolutionarily conserved; that is, that the function was present in the common ancestor of humans and fruit flies, and is so important that descendants have preserved its use.

The study suggests that research into fat storage mechanisms in fruit flies can help find potential treatments for human obesity. In the authors' words:

"Over the past few years, the number of chromosomal regions that contain one or more genes affecting obesity traits in humans and in mammalian models has dramatically increased . Results from our study indicate that D. melanogaster may be a good model to pinpoint those genes with evolutionarily conserved effects on body composition that fall within the large chromosomal regions identified in mammalian QTL studies. Our cross-disciplinary genetic study implicates a member of the laminin gene family as a novel candidate gene affecting variation in body composition traits in natural populations. These observations motivate future studies in independent human populations to verify the effects of this gene."


