As a supporter of teaching creationism and a global warming sceptic, Sarah Palin was never likely to be particularly popular among people who value science. But as the mother of a son with Down's syndrome and the aunt of a boy with autism, many will have assumed that John McCain's running-mate at least grasps the importance of medical research, particularly for children with special needs.

She certainly made full use of her experiences in a speech on disability policy last week. Millions of dollars squandered on congressmen's pet projects, she said, should be diverted to support for special needs. Taxpayers' money, she pointed out, was being wasted on “things like fruit fly research”.

It seemed a perfect example of pork-barrel profligacy. Yet her choice displayed a degree of scientific ignorance about a field in which she supposedly has expertise, that makes her famous remarks about Alaska's proximity to Russia look like wisdom.

Fruit fly research certainly isn't glamorous. To the untutored ear, it might well sound like unnecessary work that doesn't deserve public funding. However, both the specific study that Mrs Palin was discussing, and the wider field, have a huge amount to offer, not least to the special needs children her speech was intended to help.

The research she attacked is investigating natural predators of the olive fruit fly, a major pest in California. That is to say, it is designed to help American farmers to protect their crops: not quite the sort of thing you would expect the champion of “Joe Six-Pack” to sneer at.

It is her broader disdain for research into fruit flies, though, that is most worrying. For this is a discipline that has delivered some of the most important advances yet made in genetics and biology, and that continues to offer insights of great promise.

The fruit fly Drosophila melanogaster has been the workhorse of laboratory genetics for 100 years. This year marks the centenary of Thomas Hunt Morgan's first experiments with the insects, which are valuable to biologists because they breed so quickly.

The first breakthrough to which they contributed was Morgan's proof that genes are carried on chromosomes, the finger-like structures in the cell nucleus of which human beings have 23 pairs. This discovery has been critical to understanding many human diseases, including Down's syndrome, the chromosomal disorder that affects Mrs Palin's son, Trig. If medicine is to develop better treatments for this condition, fruit fly research will be partially responsible.

Since Morgan, who won the Nobel prize for his achievements, Drosophila research has contributed to many other important genetic discoveries. In the 1920s, Hermann Muller used flies to demonstrate that radiation can induce genetic mutations. In the 1980s, fruit flies allowed Janni Nüsslein-Volhard and Eric Wieschaus to show that a common set of “master genes” govern embryonic development across many species, including humans. And the insects have yielded important clues to the workings of the brain and nervous system.

Such research has recently started to make contributions to the other special needs issue of which Mrs Palin has personal experience: autism. Last year, scientists at the University of North Carolina published a study showing that proteins called neurexins are critical to nerve function in fruit flies. Other studies have implicated human genes that affect neurexins as risk factors for autism spectrum disorders.

It is hard to think of an example of supposedly profligate scientific spending that would be worse suited to making Mrs Palin's point. And it is sad that a senior politician could be so ignorant and poorly advised. Fundamental biological research, of which fruit fly work is a mainstay, is essential to the science that brings forth new medical understanding. Mark Henderson is science editor of The Times

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