1.   A gene has the particular effect that it does only because there is an existing structure upon which to work.

2.   The presence of other chromosomal deletions in colorectal cancer suggests that several more tumour suppressor genes have yet to be identified.

3.   The FAP gene has ras mutations may be important initiating events in colorectal cancer, but seem to have little independent prognostic importance.

4.   But by comparing the bodies of two adult animals that are known to differ according to a single gene, they can see what effects that single gene has.

5.   Another gene has two alleles, designated S for white spotting and s for no spotting.

6.   Because of the unity of evolution, most human genes have counterparts in lower organisms, many of which have now been sequenced and their roles ascertained.

7.   But some important eukaryotic genes have no obvious predecessors in either the archaean or the bacterial lines.

8.   But some genes have more political capital.

9.   But whatever his genes have in store, Perls intends to do what he can to stretch their potential.

10.   By their very nature, Williams said, genes have uses apart from their natural role in shaping life and contributing to disease.