Theory of ‘junk DNA’ overturned

Long stretches of DNA previously dismissed as “junk” are in fact crucial to the way our genome works, an international team of scientists said on Wednesday.

Long stretches of DNA previously dismissed as “junk” are in fact crucial to the way our genome works, an international team of scientists said on Wednesday.

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It is the most significant shift in scientists’ understanding of the way our DNA operates since the sequencing of the human genome in 2000, when it was discovered that our bodies are built and controlled by far fewer genes than scientists had expected. Now the next generation of geneticists have updated that picture.

The results of the international Encode project will have a huge impact for geneticists trying to work out how genes operate. The findings will also provide new leads for scientists studying conditions such as heart disease, diabetes and Crohn’s disease that have their roots partly in glitches in the DNA.

Until now, the focus had largely been on looking for errors within genes themselves, but the Encode research will help guide the hunt for problem areas that lie elsewhere in our DNA sequence.

Dr Ewan Birney, of the European Bioinformatics Institute near Cambridge, one of the principal investigators in the Encode project, said: “In 2000, we published the draft human genome and, in 2003, we published the finished human genome and we always knew that was going to be a starting point. We always knew that protein-coding genes were not the whole story.”