Genetic code is key to a brave new world

By FRANCESCA MOLD

A breakthrough in mapping 97 per cent of the human genetic code is already being compared to scientific accomplishments like the development of penicillin and the moon landing.

It will give doctors new insight into the causes of diseases, and increase the chance of finding cures.

What is the human genome?

It is like a genetic blueprint which whittles down the human body to a complex string of letters, giving us information about how people develop - why they are tall, thin, blond or have brown eyes.

Basically, researchers have found a way to record page after page of the letters A, T, C and G, laid out in the order they appear on the body's chromosomes.

These letters stand for adenine, thymine, cytosine and guanine - nucleotides that sit, two by two, as the "rungs" of the twisted ladder that makes up DNA.

DNA is the chemical inside the nucleus of a cell that carries instructions for making living things and is contained within 23 pairs of chromosomes.

Each three pairs of nucleotides in the DNA control production of an amino acid, which in turn creates proteins, which make up cells, hormones and everything else in the body.

How will the discovery help people?

Having a full map of the human genome will help scientists locate disease-linked genes they would never have found. They will be able to figure out if we have the kind of prostate cancer that will kill, whether our type of leukaemia will respond to one drug or another. They will eventually be able to analyse genes to rank our chances of succumbing to heart disease or Alzheimer's.

Scientists will learn which genes turn on when a wound heals, when a baby's fingers grow, when a scalp becomes bald. And they will learn to manipulate those genes.

Knowing the genetic code will help with early diagnosis and treatment of people at risk from certain diseases.

Using the genome, scientists will be able to identify "faulty" genes and replace them.

For instance, eye experts can "replace" faulty genes by inserting a virus carrying a normal gene into the retina. The virus kills the faulty gene, replacing it with the normal one.

What could it tell us about our origins?

Scientists will be able to use the "rare spelling differences" in DNA to trace human migrations.

They can recognise the descendants of certain chromosomes - for example, those that ancient Phoenician traders left behind when they visited Italian seaports.

There is already genetic data supporting the oral tradition that Bantu-speaking Lemba of southern Africa are descendants of Jews who migrated from the Middle East 2700 years ago.

Findings also suggest that 98 per cent of the Irishmen of Connaught are descended from a single band of hunter-gatherers who reached the Emerald Isle 4000 years ago.

This kind of information about our past is likely to be greatly increased with better access to our genetic makeup.

What are the dangers?

The discovery has raised a number of ethical and legal issues.

Designer people: There are concerns that the new knowledge could be used to build designer people or change hereditary patterns so that children may no longer automatically carry all the genes of their parents. Biologists may be able to use the genome as a "parts list," letting prospective parents choose their unborn child's traits.

Temperaments: Scientists already have solid leads on genes for different temperaments, body builds, statures and cognitive abilities.

Disabilities: Advocates for people with disabilities fear that the easier it becomes to change ourselves and our children, the less society may tolerate those who are different. If genetic tests in utero predict mental dullness, will society disparage children whose parents let them be born with those traits? Could it stop such children being born?

Insurance and employers: The information could also be used by health insurance companies and employers to discriminate against people with a genetic susceptibility to certain diseases. There are already examples in the US of workers being dumped by health insurers because they carried the gene for a disease that would have led to costly long-term care.

Patents: There are concerns that biotechnology companies could patent DNA sequences, restricting the knowledge to those with the wealth to pay for it.

When will suggested medical improvements become reality?

Basically, scientists have written a book but they don't yet know how to read it.

They have mapped 97 per cent of the genome so far, about 85 per cent of it accurately. But there are gaps which researchers say may be difficult, if not impossible, to close.

It is expected to take years, even decades, to decipher the information discovered so far and to make the medical possibilities it holds in diagnosing, treating and preventing disease a reality. Scientists say completion of the human genome map is the beginning, rather than the end, of the research.

Who discovered and owns the new information?

There has been a fierce scientific battle, dubbed the Genome Wars, since the mid-1990s as researchers from public and private sectors fought to be the first to make the breakthrough.

The first group was a collection of hundreds of scientists from the US, Britain, France, Germany, Japan and China working together on an international project known as the Human Genome Project, largely funded by a British charity.

The other main contender was a private biotechnology corporation called Celera Genomics, based in Rockville, Maryland, in the US.

Although Celera had promised to make its discoveries public, it was believed the company would seek to profit by selling licences to use the information and by patenting DNA sequences.

In comparison, the team of international researchers working for the publicly funded project have consistently posted every DNA sequence that they have decoded straight on to the Internet for others to use.

Last week, the two scientific foes held a joint press conference and declared that they had reconciled.

They have since revealed that 97 per cent of the human genetic code has been mapped.

How much has it cost?

The Human Genome Project is estimated to have cost $250 million so far.

Celera Genomics has not revealed how much it has spent on its research.

What happens to the information now?

Researchers can use the genetic map to identify the 60,000 to 100,000 genes in humans, to find where they are located on chromosomes and how they contribute to disease.

Doctors will also need to learn to read the code and apply everything they find to medicine.

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