Genome in a Bottle

At last the new millennium seems real. With the completion of the Human Genome Project we are finally entering the new age we all thought began on January 1 2000. For good or ill, we all will soon feel the innovations this leap in biological understanding is bringing.

Have you ever worried about getting diabetes or breast cancer? Are you concerned about your parents developing Alzheimer' s Disease as they get older, or that your children may be born with deformities? What about baldness? What would you give for a cure for hair loss? Thanks to the medical advances that knowledge of the human genome should bring, these diseases and afflictions, and masses more besides, will be things of the past. Knowledge of the human genome and how individual genes affect our bodies will enable doctors of the not-so-distant future to combat a disease before you' ve even got it. By looking at our genes a physician will know what weaknesses our body has, what diseases we are likely to get as we grow older, and how best to cure a disease should it develop. Patients will have treatments tailored specifically for them, according to their genetic profile. Proteins produced by artificially grown genes will be used to make highly effective medicines, and ultimately genes themselves will be directly injected into the body to fight everything from cancer to depression, even to old age itself.

Tiny variations

So what exactly is the Human Genome Project? A genome is all the genetic material present in each of the cells of a living thing - i.e. every gene an organism has. Each individual human being has a different genome, but the differences between each of them are incredibly small. As a result we talk about the human genome as if there were only one. However, it is these tiny variations in the genome that make you, me, Shazza and Vladimir Putin all very different people.

The current project aims to create a map of the entire human genome. It began in 1985 when scientists started listing the positions of the molecules which make up DNA, the genetic substance found in all living cells. These molecules are adenine, thymine, guanine and cytosine, referred to by their initials A, T, G and C. So the map of the genome looks like this: ATGGC GCTATCCGCAGTC..... and goes on for 3.2 billion letters! Certain combinations of these molecules make up a gene. Genes are essentially instructions which tell a cell to do something, for example make an enzyme which enables digestion in the stomach, or make a brain chemical that stimulates memory, depression and other mental states. Scientists have discovered 8,000 genes and it is estimated that humans have a total of about 80,000 of them.

Gigantic leap forward

Mapping the human genome is only the beginning of what is predicted to be a gigantic leap forward in biology and medicine. In ten years it is estimated that tests will be available for people to find out their body' s specific health risks. For example, some people who eat lots of fatty foods get heart disease in later life, and some don' t. With knowledge of people' s gene profiles we will know exactly who is at risk and who isn' t. So if you discover your body can' t cope with a lot of cholesterol you know you must be careful. And if you find out that you' ve got the genes that destroy cholesterol you will know that you can eat as much butter and lard as you like! The same goes for smoking - some people are more prone to lung cancer than others. With knowledge of our genomes we' ll know who' s who.

To some extent this knowledge is already proving useful. Having already discovered the genes responsible for prostate cancer, Alzheimer' s disease, Parkinson' s disease and breast cancer, to name just a few, doctors in the USA are already predicting health problems in patients who have had genetic tests. But these predictions are never certain and even if you have the gene for breast cancer it doesn' t mean you are definitely going to develop the disease. But at the moment genetic testing only allows doctors to discover if someone is or is not likely to develop certain diseases. With greater knowledge of the genome and how it works, they should be able to switch the bad genes off, switch good ones on, or replace them with artificially modified ones. The possibilities will then be virtually endless, and disease is just one small part of the vast field in which knowledge of the genome could change our lives.

The other side of the coin

This brings in another dimension to the debate, as we will find ourselves able to do all sorts of morally dubious things: choose the mental and physical characteristics of babies before they are born, test potential employees for genetic defects before giving them a job, genetically alter ourselves to be happier, work harder or grow old slower. In the USA people have already been fired from their jobs after having tested positive for certain killer diseases, and some health insurance companies are refusing to insure people who have nasty looking genetic profiles. Clearly new laws have to be made to protect our genetic privacy and prevent discrimination, or in the future we may find that we live in a world intolerant of genetic difference.

Many people are already getting concerned that a real" Brave New World" is not very far away. But before you start worrying that we' re all going to become emotionally identical disease-resistant clones, remember that genetics does not provide the answer to everything. Genes may well determine our behaviour and emotions, but our individuality is also the result of experience and environment and so will always stay intact. At least this is what the experts say...

Barnaby Harward