Understanding the genome
The sequencing of the 6 billion chemical “letters” of human DNA was completed in draft in 2000 and in final form in 2003. But clinical benefits have arrived more slowly than the initial hype suggested. This is mainly because the human genome actually works in a much more complex way than predicted by the late-20th-century model.
Twenty-first-century research shows that we have only 21,000 genes, one-fifth of the number predicted when the project started, and that just 1.5 per cent of the genome consists of conventional protein-coding genes. Efforts are under way to understand the vital regulatory and other functions of the non-coding regions of the genome, once dismissed wrongly as “junk DNA”.