The reference human genome combines the DNA of several people
The original of ‘the’ human genome was a reference sequence, compiled by analysing DNA from blood samples donated by a handful of anonymous volunteers. It stands as a comparison for genomes analysed later on.
That sequence covers the nuclear DNA – the DNA contained in the cell’s nucleus – which makes up over 99 per cent of the cell’s total DNA. The mitochondrion, the tiny organelle that acts as the cell’s energy generator, has its own separate genome, with 16,500 base pairs and just 37 genes. Every cell has hundreds of copies of this DNA, and many different samples have been sequenced. For more on mitochondria, see Beyond nuclear.
Since the Human Genome Project was completed, a few named individuals have had their genomes analysed. The first two were Craig Venter (the driving force behind the private genome project) in 2007 and DNA pioneer James Watson the following year. Genome analyses have since been published for individuals from three distinct geographic regions: Korea, China and Nigeria (in the latter case, one of the Yoruba people).
The results of the 1000 Genomes Project, published in 2012, catalogued genetic variations between 2,535 individuals from 26 different populations around the world. The UK followed this with the launch of UK10K, a project to sequence the genomes of 10,000 individuals, in 2010.
In the USA, Professor George Church at Harvard Medical School launched the Personal Genome Project in 2008 and was one of the first ten people on the project to make their genome sequences public (so-called ‘open-source’ publication). As the pace of sequencing increased and costs dropped, he declared his mission to sequence and publish 100,000 genomes.
In November 2013, the UK Department of Health launched the English equivalent, the 100,000 Genomes Project. Genomics England, a company owned by the Department of Health, is aiming to sequence 100,000 genomes by 2017. In all, some 40,000 patients from England will be involved. Some will be people with cancer, who will have their genomes and the genomes of their tumours sequenced. Another part of the project will sequence the genomes of people with rare genetic diseases, to help in the diagnosis (and, eventually, treatment) of these diseases.Lead image:
Sergei Golyshev/Flickr CC BY NC ND