Similar efforts are under way with plant toxins, and with poisons extracted from shellfish and puffer fish.

ECONOMIST: Suicide technologies

By contrast, Jean Weissenbach and his colleagues at Genoscope in France made their estimate by comparing the raw human sequence now available (about 60% of the total when their paper was written) with that of a puffer fish.

ECONOMIST: Out for the count | The

That makes identifying and testing open reading-frames much easier, so lots of puffer-fish genes are known.

ECONOMIST: Out for the count | The

Comparing raw human gene sequences with known puffer-fish genes suggests that the human total is around 30, 000.

ECONOMIST: Out for the count | The