Genetics

Article

The study of DNA, genes and genomes can be controversial.

On 28 February 1953, Francis Crick walked into the Eagle pub in Cambridge, England, and, announced he and his colleague James Watson had discovered 'the secret of life'. The pair had deduced that deoxyribonucleic acid (DNA) - the material in the nucleus of our cells that contains the instructions to build and maintain the body - is twisted into the shape of a double helix.

Half a century later, and we now know many of the secrets of our genome, the entire folded length of DNA in each of our cells. The genome is split into 24 chromosomes, which house our genes. These are the 'coding' parts of our DNA, which once transcribed by various cellular mechanisms actively produce new proteins - and hence make life possible. Chromosome 16, for example, contains a miscellaneous group of genes that determine what kind of earwax you have, whether or not you have red hair, and how long you are likely to live and keep all your faculties.

The DNA itself is made of four different kinds of nucleotides, known as A, T, C and G - a remarkably small number in view of the huge diversity between people, and between life forms. It is the precise sequence of these four nucleotides or 'bases' that determine whether we are a human, a mouse, or a banana, as well as the individual characteristics that make each of us unique.

In 1990, the Human Genome Project - an international, publicly funded consortium of hundreds of scientists from six different countries (the USA, France, Germany, Japan, China, and the UK) began the immense and daunting task of sequencing the three billion or so nucleotides in the human genome, and making those sequences freely available to researchers across the globe.

The final 'gold ' sequence was completed in 2003 - and analysis of the human 'book of life' could begin. There were a number of surprises within it. An early surprise was the humbling discovery that instead of the estimated 100 000 genes scientists predicted humans had, our genome only appeared to contain 22 000 - a similar number to those of a fish and fly. Another was the number of genes we share with other, seemingly disparate species: we share about 98 per cent of our genes with chimpanzees, 95 per cent genes with mice (including the gene that, if activated, could give us a tail) and perhaps 50 per cent with a banana.

Modern genetics continue to offer both benefits and controversy. Whilst advances in cloning technology may make a child of their own a breathtaking possibility for couples experiencing the pain of infertility - the notion of cloning has a sinister side, creating humans that are yet not quite human, as portrayed in Mauro Perucchetti's 'Jelly Baby'. Genetically modified plants and animals can provide us with more nutritious foods - and a possible new source of much needed transplant organs - yet may also produce unforeseen toxins, and contribute to the growing problem of antibiotic resistance. This duality is reflected in 'Bud', a glass containing genetically modified soybeans by artist Rob Kesseler.

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The study of DNA, genes and genomes can be controversial.

Video

This is a Wellcome Trust news release video about the work being carried out for Human Genome Project (HUGO) at the Sanger Centre.
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Article

James Watson was awarded the Nobel Prize together with Francis Crick in 1962 for his work identifying the structure of DNA. In this extrac