Every person is really unique

Why every person is so unique

Usually every person has two copies of every gene in their genetic make-up, one from each parent. However, when the teams compared the 270 genome sequences that came from people with Asian, European and African backgrounds, they found significant deviations from this rule in almost 3,000 genes, including duplications and missing areas. Such changes, also called Copy Number Variations (CNVs), influence the activity of the respective gene, which in turn affects the functions in the organism. The CNVs now identified by the researchers affected around twelve percent of the entire human genome due to their high average length of 250,000 building block pairs? an extent that the scientists did not expect.

“Up to now, we had always assumed that if you find such big changes, then they would inevitably be involved in a disease,” says Stephen Scherer of the Howard Hughes Medical Institute, one of the senior authors. However, since a large part of the CNVs now discovered apparently belong to normal individual variation, this approach needs to be reconsidered. At the same time, the large number of deviations indicates that the CNVs have been completely overlooked in the investigation of the cause. Around ten percent of the genes affected had previously been linked to diseases such as Alzheimer's, Parkinson's or various autoimmune diseases without any specific mutations being identified.

Another problem: the sequences that were previously used as references are also crossed by CNVs and therefore do not represent a “standard genome”. The CNV card is therefore important in order to be able to identify individual changes that do not belong to the normal spectrum. The researchers now want to build a freely accessible database that will simplify such a search.

Richard Redon (Wellcome Trust Sanger Institute, Cambridge) et al .: Nature, Vol. 444, p. 444 Razi Khaja (University of Toronto) et al .: Nature Genetics, online pre-publication, DOI: 10.1038 / ng1921 Heike Fiegler (Wellcome Trust Sanger Institute, Cambridge) et al .: Genome Research, Vol. 16, p. 1566 Daisuke Komura (University of Tokyo) et al .: Genome Research, Vol. 16, p. 1575 ddp / Wissenschaft.de? Ilka Lehnen-Beyel
November 23, 2006

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