Research reveals the root causes of diseases

The first comprehensive scientific foray into the mysteries of the human genetic code has delivered stunning insights into what…

The first comprehensive scientific foray into the mysteries of the human genetic code has delivered stunning insights into what it means to be a human. Profound is too small a word for the importance of what is being discovered.

The researchers are looking at the individual building blocks needed to produce a human. In the process the vast team of international scientists are also identifying things such as the root causes of disease, how genetic damage can cause cancer and identifying the many genes associated with behaviour.

There are also quite disconcerting findings from this research. One is the startling degree of similarity between parts of our own genetic code and the genetic code of mice, worms, even fruit flies. And the scientists have identified more than 200 human genes that were somehow inherited directly from bacteria, but which have now become essential for life.

All of these incredible findings have arisen directly as a result of two competing international efforts to sequence the entire human genetic sequence, all 3,200 million steps of it. The publicly-funded Human Genome Project (HGP) and the private firm Celera Genomics began separate efforts in the late 1990s to unravel the stunning complexity of human DNA.

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The work was aggressively competitive, with the two groups vying to be first to deliver the sequence. Yet they agreed in the end to a joint release last June, each delivering its own "draft" of the genome.

These two drafts have become the basis for an avalanche of follow-on research. Individual scientific groups working in conjunction with either the HGP or Celera have delved into the genetic code to deliver the findings which will be officially announced today at press conferences in Washington, London, Berlin, Paris and Tokyo.

While the announcements last June provided little more than a massively long list of chemical code words, today's announcements begin to reveal what the chemical code actually means in terms of life. The two sequences still remain in "draft" form although those cataloguing the genome have now captured more than 90 per cent of the total, much of this to an accuracy of 99.99 per cent.

It could be 2003 before the two groups have a final version of the sequence, but what we have so far has already provided a wealth of information. Perhaps most surprising is the relatively small number of genes needed to "build" a human, between 30,000 and 40,000.

A fruit fly needs just 13,000 genes and a cress plant 26,000. For years scientists believed that, to achieve the much greater complexity of a human, at least 100,000 and perhaps 140,000 genes would be needed. Both sequencing groups came up with this much lower figure for the number of human genes.

BOTH groups also report that our genome is highly repetitive and stuffed full of what appears to be little more than "junk", DNA with no obvious purpose. It has been likened to a cluttered bedroom or garage, highly individualistic and unkempt, with much accumulated clutter.

Think about a junk drawer, brimful of nothing in particular but where you keep essentials such as your passport, credit cards or jewellery. This is what DNA is like, with crucial life-promoting genes hidden away among long sequences of repetitive nonsense.

However, once studied in more detail, this junk is expected to reveal much. The researchers now believe that large portions of it represent ancient remnants of long "dead" DNA, formerly important but now left behind and inactive by the pressures of evolution.

The search for genes will also continue using very powerful computers and mathematical programmes that allow researchers to "mine" the sequence data for information. Many of the studies issued today were the result of data-mining, and this work will continue.

Researchers believe that these studies will lead to new ways to identify and treat diseases such as cancer. It should also bring about new and more effective drug treatments designed to respond to a person's genetic make-up.