Nucleic acid analysis

Over the past twenty years, advances in molecular biology and genetic engineering have made possible the molecular analysis of genes by studying DNA (deoxyribonucleic acid) and/or the product of their expression, RNA (ribonucleic acid). This remarkable technological advance led to the development of a considerable number of direct and indirect diagnostic methods applicable to genetic diseases as well as infectious pathologies. However, prior to 1985, these techniques rarely went beyond the research laboratory or a few specialized hospital departments. Indeed, the methods used up until then were particularly cumbersome, most often involving conventional hybridization systems (such as Southern blot) and radioactive probes. Although very powerful and widely used in research, they were not suitable for routine use due to the handling of radioactive products, the complexity of sample preparation and their cost.

In the field of molecular analysis, 1985 marked a decisive turning point with the invention of a new technique that was to revolutionize both the daily lives of molecular biologists and their way of thinking. This discovery earned its author, Kary Mullis, the Nobel Prize in Chemistry in 1993. Polymerase Chain Reaction (PCR) is an in vitro cloning technique that enables the specific amplification of a nucleotide sequence. The technology has now been perfected and is becoming increasingly popular, with commercial kits now available for the diagnosis of hereditary diseases and the detection of many infectious agents.

This means we can easily and rapidly detect the direct presence of viral and bacterial genomes, diagnose hereditary diseases using very small samples of amniotic or trophoblastic cells, monitor the appearance and evolution of malignant cells, draw up a genetic identity card from a few hair roots (forensic medicine) and, in the agri-food industry, analyze product quality, search for the presence of pathogens and contaminants, type seeds and breeds, determine the sex of embryos, and so on.