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One percent of human genes 'can be shut down without causing serious disease'

20 February 2012
Appeared in BioNews 645

Twenty completely inactive genes have been identified by scientist studying so called 'loss of function' mutations in the human genome.

The team, from the Wellcome Trust Sanger Institute in the UK, believes this work could help to identify new, disease-causing genes.

The study compared 185 peoples' genomes, looking for instances where a change in the gene affects the function of the protein it codes for. They found nearly 1,300 loss of function variants, with around 100 being found in the average European's genome. While some of these affect only one copy of the gene, meaning there may still be some functionality, around 20 occurred in both copies, and so they are completely shut down.

Dr Daniel MacArthur, first author of the study, said: 'The key questions we focused on for this study were: how many of these loss of function variants were real and how large a role might they play in human disease?'

Such variations in crucial genes are the underlying cause of a range of human diseases such as cystic fibrosis and muscular dystrophy. However, disrupting the function of other, less crucial genes might have no profound or visible effect.

Previous studies have estimated that around 3,000 loss of function variants exist in humans. However, it is not always easy to identify these variants in human genome sequences, as the sequencing process is prone to errors. So in this study other methods were used to validate these predicted variants.

Professor Mark Gerstein, co-author from Yale University, USA, explained that they found that 'at least one percent of human genes can be shut down without causing serious disease'.

The fact not all loss of function variants affect our health will be an important consideration when genome sequencing becomes more common place, as geneticist Peter Visscher of the University of Queensland in Australia told Science Now: 'This shows how careful we need to be when drawing inferences about such mutations'.

The team believes a complete catalogue of these loss of function variants will help researchers understand the genetics of rare diseases.

The study was carried out as part of the 1000 Genomes Project and was published in the journal Science.

All genes aren't indispensible
ScienceNews |  16 February 2012
A Systematic Survey of Loss-of-Function Variants in Human Protein-Coding Genes
Science |  17 February 2012
Study finds one percent of human genes switched off
Reuters |  16 February 2012
The Case of the Missing Genes
Science Now |  16 February 2012
When is a gene not a gene?
EurekAlert! |  16 February 2012
30 July 2012 - by Dr Sarah Spain 
The 1000 Genomes Project, an initiative to sequence the genetic code of 2,500 people across five continents, has now successfully sequenced over 1,000 people's genomes...
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...
28 November 2011 - by Dr Rebecca Hill 
Short people can blame deleted sections of DNA for their diminutive stature, according to a study looking at variations in the genomes of over 12,000 children...
24 October 2011 - by James Brooks 
Genes that other species do not possess may play a crucial role in making the human brain what it is. Until recently scientific consensus held that the different use of genes shared across most of the animal kingdom gave each species' brain its unique character. However this hypothesis may need some revision following a study led by Professor Manyuan Long of the University of Chicago...
18 July 2011 - by Mehmet Fidanboylu 
Two scientists claim to have pushed the boundaries of what can be learned about the ancestral history of the human race from one person's genome. Dr Richard Durbin and Dr Heng Li from the UK's Wellcome Trust Sanger Institute in Cambridge used information from the genomes of only seven individuals...
7 September 2009 - by Alison Cranage 
Scientists based at the Wellcome Trust Sanger Institute, in Hinxton, Cambridge UK, have used ‘next generation sequencing technology' to work out the mutation rate in the human genome. The international team's findings were published in Current Biology last week....
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