Uusia tuulia genetiikassa

Eräät tämän päiväiset tiedejulkaisut (ja eräiden muidenkin lehtien tiedesivut) kertovat tiedemaailmaa yllättäneestä uutisesta genetiikan saralta. Ennen ajateltiin, että "elämän kirja" olisi erittäin samanlainen kaikilla ihmisillä, eroten vain joidenkin "sanojen" kohdalla. The Independent-lehden tiedetoimittaja Connor kuvaa tänään julkaistuja uusia löydöksiä siten, että nyt ollaan havaittu että ihmisten perimissä onkin erilaisten "sanojen" lisäksi myös erilaisia "lauseita", "kappaleita", ja jopa erilaisia "sivuja". Eri ihmiset ovatkin vähintään 10 kertaa erilaisempia keskenään, kuin ennen ajateltiin. Professori Lupski kuvaa tutkimuksen uusien löydösten suurta merkitystä todeten, että kyseinen tutkimus tulee muuttamaan ihmisgenetiikan kentän. Jäljessä seuraa sitaatti The Independent-lehden uutisen alkuosasta. Uutisen voi lukea kokonaisuudessaan (samoin kuin Naturessa julkaistun varsinaisen tutkimuksenkin) jäljessä seuraavista linkeistä.

23.11.2006
Genetic breakthrough that reveals the differences between humans
Scientists hail genetic discovery that will change human understanding
Steve Connor, Science Editor, The Independent (online edition)

Scientists have discovered a dramatic variation in the genetic make-up of humans that could lead to a fundamental reappraisal of what causes incurable diseases and could provide a greater understanding of mankind.

The discovery has astonished scientists studying the human genome - the genetic recipe of man. Until now it was believed the variation between people was due largely to differences in the sequences of the individual "letters" of the genome.

It now appears much of the variation is explained instead by people having multiple copies of some key genes that make up the human genome.

Until now it was assumed that the human genome, or "book of life", is largely the same for everyone, save for a few spelling differences in some of the words. Instead, the findings suggest that the book contains entire sentences, paragraphs or even whole pages that are repeated any number of times.

The findings mean that instead of humanity being 99.9 per cent identical, as previously believed, we are at least 10 times more different between one another than once thought - which could explain why some people are prone to serious diseases.

The studies published today have found that instead of having just two copies of each gene - one from each parent - people can carry many copies, but just how many can vary between one person and the next.

The studies suggest variations in the number of copies of genes is normal and healthy. But the scientists also believe many diseases may be triggered by an abnormal loss or gain in the copies of some key genes.

Another implication of the finding is that we are more different to our closest living relative, the chimpanzee, than previously assumed from earlier studies. Instead of being 99 per cent similar, we are more likely to be about 96 per cent similar.

The findings, published simultaneously in three leading science journals by scientists from 13 different research centres in Britain and America, were described as ground-breaking by leading scientists.

"I believe this research will change for ever the field of human genetics," said Professor James Lupski, a world authority on medical genetics at the Baylor College of Medicine in Houston, Texas.

Professor Lupski said the findings superseded the basic principles of human genetics that have been built up since the days of Gregor Mendel, the 19th century "father" of Mendelian genetics, and of Jim Watson and Francis Crick, who discovered the DNA double helix in 1953.

"One can no longer consider human traits as resulting primarily from [simple DNA] changes... With all respect to Watson and Crick, many Mendelian and complex traits, as well as sporadic diseases, may indeed result from structural variation of the genome," Professor Lupski said.

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