Flies offer hope to infertile men

Humans and flies share certain fertility genes

Scientists have cured infertile flies in a development that offers hope for men with low sperm counts.

Work on animals as simple as fruit flies can provide important breakthroughs for human biology

Dr Matthew Gage

Researchers in the US were able to switch on sperm production by injecting a key gene into infertile flies.

The same thing happened when the equivalent human gene was given to flies.

The research could lead to new ways to tackle male infertility or, paradoxically, help in the development of male contraceptive pills.

Key gene

The work was carried out by a team at the University of California San Francisco.

They looked at flies that are unable to produce sperm because of the loss of a key gene which controls meiosis (the division of sperm and egg cells).

The same gene - BOULE - exists in humans, suggesting a target for research into new treatments.

"The identification of genes such as BOULE that are required for meiotic function are likely to be important clinically," said Dr Eugene Yujun Xu.

"We've opened the box on the BOULE molecular pathway. Now we must look further to see what other conserved genes are regulating human meiosis."

Mice and men

About 30% of infertile men have a problem in which sperm cells stop dividing before they reach maturity.

It might one day be possible to develop a drug that overcomes this, according to the researchers, who publish their findings in the journal Human Molecular Genetics.

The gene is also a target for a possible male contraceptive pill.

By blocking the action of the gene, it might be possible to stop mature sperm being produced without harming future fertility.

The scientists now plan to carry out similar experiments on mice to see if the results can be replicated.

'Groundbreaking'

Commenting on the research, Dr Matthew Gage of the University of East Anglia in Norwich, UK, said genes such as BOULE were similar across a big range of organisms.

He told BBC News Online: "What this groundbreaking work does show is that there is still much to be learnt concerning the biology of reproduction, and that work on animals as simple as fruit flies can provide important breakthroughs for human biology."

Since about one third of infertile men suffer as a result of disruptions within meiosis, the research can target the genetic problem, and possibly in the future rectify it, he said.

Professor Chris Barratt of the School of Biosciences at the University of Birmingham, UK, said gene therapy to treat male infertility would take a long time to perfect.

"The principle is an exciting one but a clinical application is some years away," he said.