Genome Health Dictionary

In simple terms, this is the genetic recipe for making a human being. GENOME is a combination of the words gene and chromosome, and a genome is de?ned as all the genetic material – known as deoxyribonucleic acid, or DNA – in a cell. Most genes encode sequences of AMINO ACIDS, the constituents of proteins, thus initiating and controlling the replication of an organism. The identi?cation and characterisation of the human genetic puzzle have been a key bioscience research target. The Human Genome Project was launched in 1990 (and completed in 2003) to produce a full sequence of the three million base pairs that make up the human genome.

Carried out as two separate exercises – one by a privately funded American team; another by an international joint venture between tax-funded American laboratories, a charitably funded British one and several other smaller research teams from around the world – the ?rst results were announced on 26 June 2000. In February 2001 the privately funded American group, known as Celera Genomics, announced that it had identi?ed 26,558 genes. At the same time the Human Genome Project consortium reported that it had identi?ed 31,000. Allowing for margins of error, this gives a ?gure much lower than the 100,000 or more human genes previously forecast by scientists. Interestingly, genes were found to make up only 3 per cent of the human genome. The remaining 97 per cent of the genome comprises non-coding DNA which, though not involved in producing the protein-initiating genetic activity, does have signi?cant roles in the structure, function and evolution of the genome.

One surprise from the Project so far is that the genetic di?erences between humans and other species seem much smaller than previously expected. For example, the Celera team found that people have only 300 genes that mice do not have; yet, the common ancestor of mice and men probably lived 100 million years or more in the past. Mice and humans, however, have around twice as many genes as the humble fruit ?y.

Cells die out when they become redundant during embryonic development: genes also die out during evolution, according to evidence from the Genome Project – a ?nding that supports the constant evolutionary changes apparent in living things; the Darwinian concept of survival of the ?ttest.

Apart from expanding our scienti?c knowledge, the new information – and promise of much more as the Genome Project continues – should enhance and expand the use of genetic engineering in the prevention and cure of disease. Studies are in progress on the gene for a receptor protein in the brain which will shed light on how the important neurotransmitter SEROTONIN in the brain works, and this, for example, should help the development of better drugs for the treatment of DEPRESSION. Another gene has been found that is relevant to the development of ASTHMA and yet another that is involved in the production of amyloid, a complex protein which is deposited in excessive amounts in both DOWN’S (DOWN) SYNDROME and ALZHEIMER’S DISEASE.... human genome

The complete set of human genetic material. The human genome consists of 23 chromosomes, which, together, contain about 30,000 genes. All body cells contain 2 sets of the 23 chromosomes, one set inherited from the father and the other from the mother. An international research programme, the Human Genome Project, was launched in 1990 with the aim of identifying all the human genes. The first rough draft of the project was published in 2000.... genome, human

a massive international research project to isolate all the genes in human DNA and determine the sequence of genes on human chromosomes. The project began in 1988 and the full draft sequence was published in 2001; the high-quality sequence was completed in 2003. The human genome comprises some 3 × 109 nucleotide base pairs (see DNA) forming 22,000–25,000 genes, distributed among 23 pairs of chromosomes. Knowledge of the entire human genome has already resulted in the identification of the genes associated with many hereditary disorders and revealed the existence of a genetic basis or component for many other diseases not previously known to have one. Theoretically, this would enable the development of targeted drugs and the large-scale genetic screening of populations. See pharmacogenomics; targeted agent.... human genome project