DNA pioneer reveals genetic secrets

Craig Venter, the pioneering DNA researcher, on Tuesday published the most detailed analysis ever of an individual’s genome – his own.

The study, carried out at his J. Craig Venter Institute in Maryland, shows that Dr Venter carries genes that may predispose him to Alzheimer’s and heart disease, novelty seeking behaviour and a preference for evening rather than morning activity. Never before has anyone revealed so much personal information in a scientific paper.

On the scientific plane the study – published in the journal PLoS Biology – adds new evidence to other studies showing human genetic diversity is much greater than scientists assumed when the first two versions of the human genome were published, with great scientific fanfare, in 2001.

These original DNA sequences, one obtained by the publicly funded Human Genome Project and the other by Dr Venter and colleagues at Celera Genomics, were a mosaic built up from various donors. In Celera’s case, Dr Venter contributed 60 per cent of the DNA and four other people the remaining 40 per cent. But the effect of melding genomes to obtain a “consensus sequence” was greatly to underestimate genetic diversity, Dr Venter told a press teleconference on Tuesday.

The new sequence, called HuRef, is a complete “diploid genome”. It contains 6bn chemical units of DNA – half inherited from Dr Venter’s mother and half from his father. In contrast, the original consensus genomes contained 3bn units each.

HuRef makes it possible for the first time to determine the amount of variation between the two parental chromosomes. The answer was surprisingly large – although recent research funded by the Wellcome Foundation, comparing many human genomes sequenced in much less detail than Dr Venter’s, was already pointing in this direction.

“Each time we peer deeper into the human genome we uncover more valuable in­sight into our intricate biology,” said Dr Venter. “With this publication we have shown that human-to-human variation is five- to seven-fold greater than earlier estimates, proving that we are in fact more unique at the individual genetic level than we thought.”

Scientists at the Venter Institute have been working on the HuRef project since 2003, using traditional sequencing technology that still gives the most accurate results but costs tens of millions of dollars per genome. “Mine will probably be the first and last genome to be sequenced in this way, because of the cost and time involved,” said Dr Venter.

Much faster and cheaper, but slightly less accurate, DNA sequencing techniques are now becoming available that will soon make it possible to obtain a genome for a few thousand rather than millions of dollars.

Dr Venter said he had no hesitation in publishing his own genome – and he attacked “the old notion that genetic information was top secret and should not be disclosed to anyone”.

“What we are all going to find out is that, with some very rare exceptions, every human trait is a statistical probability resulting from a number of genes working together,” he added.