The Sceptic: Flies like us

"Am I not/A fly like thee?/Or art not thou/A man like me?" So wondered William Blake. Today we know that human beings and flies are made of essentially the same stuff. Sixty per cent of human genes have similar counterparts in flies. A paper published last month by the journal Nature Genetics showed how the gene TTC19, which is mutated in some rare brain disorders in man, is also found in the humble fruitfly, Drosophila melanogaster. The fly also shows brain malfunction when the gene is mutated.

The study is the latest in a long line linking the biology of human beings with flies. It takes just a week for a fertilised Drosophila egg to metamorphose into an adult fly. All of life's processes can be studied in fast-forward, which accounts for the popularity of Drosophila among scientists. Some even advocate the systematic testing of drugs on fruitflies, and programmes into Alzheimer's, Parkinson's and Huntington's disease are under way. Breakthroughs are yet to come, but the basic idea is sound; there is no doubt that learning about flies speeds up our learning about ourselves.

This might surprise Sarah Palin, who railed against public funding of fruitfly research during her 2008 US election campaign. But Palin is a confirmed creationist, doubtful of the proposed links between man and his simian cousins - let alone a tiny arthropod.