Gene chip: the possible impact of the gene chip on future medical practice

Citation

Brennig James, D. (2000), "Gene chip: the possible impact of the gene chip on future medical practice", Kybernetes, Vol. 29 No. 2. https://doi.org/10.1108/k.2000.06729baf.002

Gene chip: the possible impact of the gene chip on future medical practice

Gene chip: the possible impact of the gene chip on future medical practice

Keyword: Genetics, Medical, Chips

Product of our genes

Medicine for the most part is a process of diagnosis followed by treatment. Ninety per cent of the effort is directed to diagnosis and the remainder to treatment. Most of the information is obtained verbally from the patient, history taking, followed by examination and special investigations such as blood analysis. Medicine is determined by pathology and could well be described as applied pathology. Studies of identical twins separated at birth show that they resemble each other more closely than those brought up together, so, while development may be greatly influenced by common factors in the environment such as gravity or the properties of water, the differential factors seem to have little effect at all and we can state that the individual is totally the product of his genes. This must include pathology as well, since abnormalities in the genes must be reflected in the phenotype.

DNA on a chip

The number of DNA bases in the haploid genome is 3.6 billion and three errors can occur at each location, so the total number of single ways in which a cell can be abnormal is ten billion, the names of which medical students of the future must all learn off by heart. Multiple errors will number factorial ten billion, but the number of diseases to which the human is subject is much less than that. Perhaps about ten thousand, so the actual process of diagnosis is a matter of fitting a patient into one of these categories. Diagnosis is partly a matter of pattern recognition and partly one of logical deduction although the two are difficult to separate.

There are about 80,000 genes in the human body, each with a unique sequence of DNA bases by which they can be recognised by hybridisation with their complementary DNA. Patches of complementary DNA can be immobilised on a suitable chip to form an array which could in theory recognise the absence or presence of all 80,000 genes. This will hardly be necessary since the majority of gene deletions are incompatible with life, so a patient lacking a gene required to make the heart is unlikely to present. So a gene chip which recognises the 5,000 genes likely to be relevant seems entirely possible, and in addition methods such as PCR will increase its sensitivity.

It can be mass produced and washed after use, so cost may not be a barrier to its use.

What will happen will be that the patient starts an examination by giving a sample of DNA either from a mouth swab or a blood sample. This is assessed by the gene chip and compared to a databank in a PC or the Internet, giving a vast amount of information available to the doctor before the patient enters the surgery, in effect a reversal of the information flow since the consultation commences with the special investigation. The gene chip will have an enormous influence in biological research since many genes are conserved and the method is both quick and cheap; in medicine its influence may start quite soon, and its effect could be revolutionary.

Dr Brennig JamesCherry Orchard, Marlow Common Buckinghamshire, UK