4th quarter 2004

The human genome becoming increasingly clear — Fewer errors, fewer gaps

In autumn 2004, the international consortium for decoding the human genome presented a revised and nearly complete version of the human genome sequence. Some 2,800 scientists from 20 institutes in the USA (60%), United Kingdom (30%), Japan (5%), France (3%), Germany (1%) and China (1%) were involved in this mammoth project (the figures in brackets indicate the nations' respective contribution to the current human genome sequence).

The revised version covers 2.85 billion of the approximately 3.08 billion components of our genetic code. Printed on A4 format paper, this would roughly correspond to a million pages. Of the segments of the human genome containing many genes, genome researchers have thus deciphered more than 99%.

In the first draft version published in 2001, which covered about 90% of the human genome, the sequence and orientation of many sequenced segments still remained unclear. Moreover, these segments were interrupted in about 150,000 places. There are merely 341 gaps in the present version, and the error ratio is very low — an average of one in 100,000 components of the sequence are wrong. This corresponds to one wrong letter in a book of 100 pages.

The genome centres that have had responsibility thus far are still aiming to close the remaining gaps. Since it is necessary to develop new methods to do so, it is impossible to foresee when the human genome sequence will be available in full.

Researchers have again made a downward correction in the number of genes in our genome that represent the "building instructions" for proteins. This number, which had still been estimated at about 30,000 in the draft version of 2001 (prior to the Human Genome Project, a figure of 100,000 had been assumed), scientists now put the number of genes that code for proteins at somewhere between 20,000 and 25,000.

The human genome sequence will serve as a basis for further concerted research projects

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  The aim of the Encode Project is to compare our genome with that of other organisms and to identify not only other genes but also regulatory areas and other functional elements in our genetic code.
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  The Hapmap Project will search for individual variations associated with diseases, successful therapies or side effects in the genomes of Asians, Africans and Europeans.

The mid-term objective of these projects is to gain a better understanding of an individual genome and thus create the conditions for personally tailored medicine.

The human genome sequence will provide the basis for 21st century medicine. It will allow a better diagnosis of diseases. Once the genetic makeup of common diseases is known, predictive genetic tests will become available. The human genome sequence will help the drug industry design novel types of medication. It will also help advance experimental therapies such as genetic therapy or stem cell therapy.