Think of a Small Biological Computer

Scientists of the Weizmann Institute of Science in Israel have programmed

the world’s smallest computer to detect cancer of the prostrate and

lung. The team of scientists guided by Prof. Ehud Shapiro (photo) used a

computer they had designed and made entirely of biological molecules. An

idea of the size of the computer can be imagined by pointing out that a

drop of water can hold about a trillion (one million million) of such

computers!The biological molecules constituting the computer consist of three units:

input, computation and output. The input unit is made up of short strands

of deoxyribonucleic acid (DNA). These DNA molecules contain all the vital

information about the genes in living cells and formulae for all life processes.

These molecules check for the presence of a single-strand substance called messenger ribonucleic  acid (mRNA). The mRNA is controlled by four chosen genes. If cancer has set in, the four genes in the cell would have become under-active or over-active.

The computation unit, consisting of a long hairpin-shaped DNA strand, then checks each input

in turn. Only if all the four genes point to cancer will the computation unit give a diagnosis of

cancer. The computation unit also contains the third unit or component of the bio-computer which is again a single strand DNA known to have the potential to fight cancer. If the diagnosis by the computation unit reveals cancer in all the four genes, the third unit DNA activates its fighting

potential. There is thus a possibility that in the not-too-distant future, cancer can be diagnosed and treated even without looking for the appearance of symptoms.