Locked inside your body, amongst the tiny strands of DNA are the secrets of what makes you who you are; your body, your life and your personality.
The human genome is the complete description of every one of the genes that you carry within you, and your body contains about 20,000-25,000 of them. Basically, the human genome is a kind of genetic instruction manual for building a human being.
It is inaccurate to speak of ‘the’ human genome, as every human genome is different, but not by much. Your genes are 99.9 per cent the same as everyone else’s but that crucial 0.1 per cent difference is what makes you an individual.
To know your genome would be like finding out what characteristics you have inherited from your parents before you have even grown up. You would be able to tell what you will look like, what diseases you are most at risk from and, to an extent, how you will behave and even when you might die.
Mapping the genome was a worldwide project. The Human Genome Project was the largest ever international collaboration in biology. It was coordinated by the US Department of Energy and the National Institutes of Health and combined the efforts of researchers from countries including the UK, Germany, France and Japan. It main purpose was to work out the sequence of all three billion letters in human DNA and to label the precise whereabouts and function of each gene.
Secondary goals were to store this information, transfer the technologies to the private sector for medical applications and address ethical, legal and social issues. Launched October 1990, the project was planned to last 15 years, but advancements in technology accelerated its completion. In June 2000 it was announced that the first working draft of the human genome was complete. The scientists completed a high-quality, finished sequence in 2003.
The complicated process of mapping the many thousands of genes in the human body took much time and many scientists, but what will its completion mean?
The human genome is made up of a chemical called deoxyribonucleic acid, or DNA, which is bundled up in the nucleus of every one of the 100 trillion cells in the human body. For the most part DNA doesn’t appear to do anything apart from replicate itself. In fact, 97 per cent of human DNA is meaningless and is called junk DNA by scientists.
One here and there along strands of DNA do you find the genes that determine how an individual will develop.
DNA has four basic components, called bases, and these are: adenine, thiamine, guanine, cytosine.
The shape of a DNA molecule is like a twisted ladder, the famous double helix. The steps of the ladder are formed by the bases joining in pairs and the order in which they appear as you move along the ladder make up the DNA code.
Determining the exact order, or sequence of the 3 billion bases that make up the genome has therefore been a huge task. However, the Human Genome Project has managed to achieve this goal and has been able to reveal the genes within your DNA as well as the regions controlling the.
How did the scientists working on the Human Genome Project decode the DNA that makes up the human genome?
First, vast sequences of DNA were chopped up into more manageable sizes using special enzymes. The fragments were fed to bacteria to produce millions of copies, giving even more raw material to work with.
The cloned fragments were then divided into four special solutions. Each of these contained chemicals that could recognize which of the four basic components of DNA were present. When the particular component was identified, a fluorescent tag was added.
The tagged components were then put into this gel-filled tubes where an electric charge was added, causing the smallest of the components to travel faster than the large ones and thus sorting them according to size.
Eventually, all of the different components were separated and ordered. The fluorescent tags at the end of each fragment could then be read off by a laser, giving the correct genetic sequence for that particular piece of DNA.
The completion of the Human Genome Project has heralded the dawn of a new genetic age that has thrown up a number of moral issues. On the plus side, it promises the possibility of eradicating genetic illnesses by repairing the damaged gene before the illness has arisen.
What’s more, scientists believe that, within the near future, it should be possible to modify genes to make designer babies. Scientists believe that it will be possible for parents to alter the genes of their children to enhance such things as their intelligence, beauty and health.
However, just because a thing can be done, does it mean it should be? Many argue we don’t have the right to play God and that engineering a gene into a person could have unforeseen side effects. These are just some of the dilemmas facing humankind. Knowledge of the human genome is sure to bring potentially huge medical advancements, but it is up to use to use them wisely.
