Conquering the human genome

Today we are opening a new era in human biology and medicine. Two rival teams of scientists this week present their first interpretations of the human genome, which is the set of encoded DNA instructions that specify a person.

A team, Celera Genomics, has compiled a list of parts of the proteins needed to make a person. The other team, a state-funded consortium, traced the story of how “junk” regions accumulated genome and found that small elements of the junk can play a useful role. They also discovered that human genes were obtained directly from bacteria. The two teams announced last they had assembled the human genome, but it will take a little longer to properly analyze the results.

The interpretation of the human genome

The identification of genes, their functions and controls, and how they relate to human physiology and disease – is expected in time to revolutionize medicine by clarifying the mechanism of many diseases and generating new tests and treatments .

Physically, the genome is tiny – two copies of it are packed in the core of every ordinary human cell, and each of them is about one-fifth the size of the smallest grain of dust that the eye can see . But the genome is vast in terms of informational content. Composed of chemical symbols designated by a four-letter alphabet of A, T, C, and G, the human genome is some 3.2 billion letters in length. If printed in standard characters, it would cover 75,490 pages of this newspaper.

The enormous task of decoding the genomic message began in 1990 and is now almost complete, although the versions of both genome teams are riddled with gaps.

With so much effort and scientific brilliance at stake, the members of each team remain highly critical of the other approach, believing that their own strategy for decoding the genome is likely to produce the better and more accurate version. Since June, however, both have had criticisms of inhibition and observe a limited truce. The pact called for a joint announcement, made at the White House on June 26 last year, that each party had finished assembling its version of the genome, and joint publication of their findings, which occurs later this week .

The joint publication, however, is about as separate as a union could be, with articles from each party appearing in rivals published scientific journals on different sides of the Atlantic. The results were to be announced tomorrow, but the embargo was lifted by the two journals after The Observer of London, it broke.

One team is a consortium of academic centers, primarily in the United States and Britain, but with members in France, Germany, China and Japan. The consortium is funded largely by the National Institutes of Health and the Wellcome Trust in London. His version of the human genome is described in a 62-page article in the journal Nature, based in London. The lead author is Dr. Eric Lander of the Whitehead Institute in Cambridge, Massachusetts

The other team is led by Dr. J. Craig Venter, President of Celera Genomics in Rockville, Maryland His report is featured in a 48-page article in Washington-based Science.

Despite the many differences between the two teams, they largely agree on their findings on the human genome. It is their first glance at a genetic document of extraordinary strangeness and complexity. Nobody expected it to be understandable at first glance and both teams have so far mapped only the main features of its terrain.

Their main discovery is how many human genes there seem to be. Textbooks have long fixed the number of human genes at around 100,000, but with the sequence of units of the human genome in hand, the two teams found much less than expected. Dr. Venter says he has identified 26,588 genes encoding proteins for you and another 12,000 possible genes. The consortium says there are 30,000 to 40,000 human genes. Both parties prefer the lower end of their range, their gene discovery methods tend to predict more genes than they think exist.

The low number of human genes – say 30,000 – can be considered good for medicine because it means there are fewer genes to understand.