21.   Genes make proteins, but many proteins made by cancer genes are not yet known.

22.   Genes serve as a script that directs the body to make proteins.

23.   Genes are the instructions for making proteins.

24.   Genes carry the instructions for making proteins.

25.   Genes, which are segments of DNA, are of interest to drug companies primarily because they are the recipes for making proteins.

26.   Gene-hunting companies such as Human Genome Sciences and Incyte Genomics finds genes by catching them in the act of making proteins.

27.   However, the way in which the genes made proteins was flawed and unstable.

28.   Human Genome Sciences found its genes by catching cells in the act of making the proteins, without knowing at first what the genes did.

29.   If anything, it intensifies the challenge, because the gene mappers showed that many human genes make several proteins.

30.   In prehistoric days when food was scarce in cold, dry areas, tyrosine was probably conserved to make essential proteins, Mackintosh says.