QI QUESTIONS

Sixteen Curiosities from

the QI Vaults

1 . What drives human sperm wild? The smell of Lily of the Valley.

It appears sperm have “noses” which they use to navigate towards a woman’s egg. Researchers experimented with a range of floral fragrances and Lily of the Valley came top, getting the random sperm wiggling in the same direction at twice the normal speed.

The research was carried out at Ruhr University in Germany in 2003. They discovered a new sperm protein, hOR174, which acted as a receptor for sperm in exactly the same way as protein sensors in the nose detect smells. They then tested their new sperm “nose” on hundreds of synthetic compounds, many of them used to mimic floral scents in commercial perfumes.

One of these, bourgeonal, is used to create the Lily of the Valley fragrance. It had two dramatic effects on the behavior of sperm: doubling its speed and changing undirected swimming behavior to direct movement. The “foot-to-thefloor” effect seems to derive from hOR17-4making the sperm wag their “tails” harder.

Bourgeonal is now being used in fertility treatment to pick out the Mark Spitzes of the sperm world.

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THE IDLER

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SUMMER 2008