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We all have hundreds of defective genes, study finds

1 November 2010
Appeared in BioNews 582

A four-year, £75m project to discover novel variations between human genomes has completed its pilot phase. Among the 1000 Genomes Project's initial findings are each person carries around 250 - 300 genetic mutations. Scientists have previously linked 50 - 100 of these mutations to inherited diseases.

Eight million previously unknown variations were found in SNP (single nucleotide polymorphism) - the building blocks of genes. The study also revealed one million structural variations, such as repeated or deleted DNA sequences and rare differences in the genetic code that occur in only one percent of the population.

The pilot phase of the project sought to develop and compare several different methods of genome sequencing on a sample population of 800 people. The project will go on to sequence the genomes of 2500 people from each of the five major population groups, in the hope at least 95 percent of existing genetic variations will be revealed.

Co-chair of the project Dr Richard Durbin told the Guardian: 'In the last 10 years, DNA sequencing technology has advanced dramatically so it becomes feasible to systematically sequence many people to find genetic variants'. He continued: 'Over half those differences haven't been seen before, and these have provided a more complete catalogue of variation than was available previously'.

179 people had their whole genomes sequenced during the project's pilot phase using 'low-coverage' sequencing - in which a small amount of random DNA is sequenced for each individual. 697 people only had their protein-coding regions called 'exons' sequenced, which are responsible for most important variations, despite accounting for a minority of DNA.

The project found 'low-coverage' and 'exon' sequencing could be used with relatively low error rates. The results of the study were published as part of a series of papers in the journals Nature, Science and Genomic Research.

1000 Genomes Project completes first map of human genetic variation
Guardian |  27 October 2010
New genome study proves that nobody’s perfect
Times |  28 October 2010
Pilot Phase of 1000 Genomes Project Identifies 8 Million New Genetic Variants
GEN |  28 October 2010
Scientists from 1,000 Genomes Project have identified 95 per cent of genetic variations
The Telegraph |  27 October 2010
The 1000 Genomes Project
Nature |  28 October 2010
21 May 2012 - by Dr Linda Wijlaars 
Rare genetic variants - those carried by fewer than five in 1,000 people - are much more common than previously thought, according to two studies published in Science...
20 June 2011 - by Dr Sarah Spain 
In the first direct measure of new mutation rates in humans, researchers have found that when parents pass their genes down to their children an average of 60 mutations are introduced into the genetic code during the process...
28 June 2010 - by Dr Vivienne Raper 
The largest study of genetic differences between people to date - the 1,000 Genomes Project - has completed its pilot studies. The data is now freely available...
27 January 2008 - by Dr Jess Buxton 
An international project to read the entire genetic code of at least 1000 individuals will result in a comprehensive catalogue of human variation that will accelerate efforts to identify genetic factors involved in health and disease, scientists announced last week. The '1000 Genomes Project' will take...
9 October 2006 - by Antony Starza-Allen 
The X Prize Foundation is offering $10m to the first private team that is able to sequence 100 human genomes in just ten days. It would currently take months, at the cost of millions of dollars, to sequence an individual human genome. Francis Collins, director of the...
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