Increasingly, genome hunters are chasing bigger prey. We rely on plants to feed, clothe and house us, and yet we know very little about what makes them the way they are. Plants are remarkably different from animals, fungi and microbes. And they create a vast range of chemicals, the synthesis of which still taxes the most ingenious chemists. The basic ingredients of the world's medicine cabinets started life in plants, as well as the stock of the illegal drugs trade.
Plant genomes are likely to be full of interest.
But we know enough about plant genomes to know that they are sometimes very large, and littered with short, highly repetitive elements. Both problems are serious for gene-sequencers. Help is at hand, however, in the unlikely form of Arabidopsis thaliana , a tiny plant of the cabbage or 'brassica' family that is related to mustard. Although Arabidopsis may be just a little weed to you and me, geneticists love it because it has all the functions and anatomy of a plant but a relatively small genome, uncluttered by repetitive sequences. The sequences of chromosomes 2 and 4 of Arabidopsis are reported in the latest issue of Nature .