Copying out our ABCs: the role of gene redundancy in interpreting genetic hierarchies.

The complete sequence of the Arabidopsis genome is scheduled to be determined by the end of the year 2000. While this goal could prove to be something of a moving target (the estimated size of the genome has grown from 120 Mb to 130 Mb over the last year1), it is clear that the majority of genes required for higher plant growth, reproduction and development will have been described within this time frame. Some of the implications of this landmark achievement are already becoming clear, even though less than a half of the genome has been sequenced.