For years I was instructed that human beings and chimps were basically the same animal, aside from a 1% genetic variation that made the building of cathedrals, the writing of Shakespeare’s plays, and the invention of the internet possible for humans and impossible for chimps. I think most of us found that marvellous 1% a bit dubious.

Now we learn from findings simultaneously released in Britain and America that each of us is genetically ten times more unique than we thought and that we and chimps differ a bit more – the genetic difference is supposed to be 4%.

The Independent reports that

The new discovery has astonished scientists studying the human genome - the genetic recipe of man. Until now it was believed the variation between people was due largely to differences in the sequences of the individual " letters" of the genome.

It now appears much of the variation is explained instead by people having multiple copies of some key genes that make up the human genome. These are called copy number variations (CNV).

According to the Telegraph,

"Each one of us has a unique pattern of gains and losses of complete sections of DNA," said Dr Matthew Hurles, one of the project's leaders at the Wellcome Trust Sanger Institute, near Cambridge, "and one of the real surprises of these results was just how much of our DNA varies in copy number. The copy number variation that researchers had seen before was simply the tip of the iceberg, while the bulk lay submerged, undetected."

. . .An understanding of how genetic variation is distributed among populations not only tells us about human prehistory but also improves our ability to find disease genes, added Dr Nigel Carter, another of the project's leaders at the Wellcome Trust Sanger Institute. "In particular, we feel they may have a role in the diseases of old age."

. . .Of the approximately 3,000 genes that vary in copy number from their predicted two copies, 285 are already known to be associated with disease.

The Wellcome Trust has been a leading player in gene research, and so successful that last year the United States National Cancer Institute (NCI) backed the Trust with $1.35 billion (£725 million) over nine years to trace DNA mutations in cancer, as we describe here, in the Ingenious Timeline.

What causes the copy number variations to differ? What is the effect of those variations? As one of the doctors remarked, the stage is set for future study – and future corrections to what we think we know.