Fruit fly genome provides evolutionary insight

Scientists have cracked the DNA code of a dozen different species of fruit fly, a tour de force that will lay bare new details of how evolution works.

The study will shed light on human medicine too and has already revealed that earlier methods to find genes are flawed.

The fruit fly is the world's favourite laboratory animal because many of their genes correspond to those in humans and control the same biological functions, a fact underlined how today's study was carried out by hundreds of scientists from over 100 institutions in 16 countries.

"The evolution of the fruit fly is interesting in itself as, basically, they have been following us around the planet as we discard rotting fruit - they started off in Africa with us - now are everywhere," said Dr Ewan Birney of The European Bioinformatics Institute, Cambridge, who comments on the work in Nature.

"Now these fruit flies, who have been our evolutionary companion as we left Africa, repay us by giving insights into their genome. Flies can remember things, they can get drunk," he said, listing some of the ways they will help human medicine.

"Their evolution is particular interesting, especially in Hawaii where there are these weird super-sized flies," he said, adding that he expected the work will pave the way for similar comparisons of mammalian genomes.

More than 40 manuscripts related to these studies are forthcoming, in addition to the papers published today in the journal Nature.

The studies reveal new details of how genes are regulated- turned on and off - which is important to understand how relatively few genes - around 14,000 and 20,000 respectively, - can build an organism as complex as a fruit fly or a human being.

Genes are messages written in DNA that control the manufacture of the proteins the build and operates our bodies. Today's papers also reveal major flaws in the way scientists identify genes.

They found 1,193 new DNA sequences that encode proteins, 414 regions that were mistakenly labelled as protein-coding genes, and made corrections to hundreds of stretches of DNA previously thought to be protein-coding genes. The resulting corrections will affect 10% of all fruit fly genes.

The scientists also learned certain genes appear to be evolving faster than others, such as the genes associated with smell and taste, sex and reproduction, and defences against disease.

"Having the sequences of many closely related species allows us to study the evolutionary forces that have shaped the fruit fly's family tree," said Manolis Kellis, associate member of the Broad Institute, near Boston.

"This remarkable scientific achievement underscores the value of sequencing and comparing many closely-related species, especially those with great potential to enhance our understanding of fundamental biological processes," said Dr Francis Collins, director of the US National Human Genome Research Institute, Maryland.

"Scientists around the world now have a rich new source of genomic data that can be mined in many different ways and applied to other important model systems as well as humans."