ABSTRACT
Two major factors have been contributing to this accelerated increase in our knowledge. The first factor is related to the recent elucidation of the DNA sequence of the human genome and the identification of hitherto unknown genes, which have revolutionized science. This major achievement has primarily yielded a large amount of new information. The great challenge nowadays, however, is not so much obtaining the information but rather its interpretation. The human genome has approximately 97 percent of ‘junk’ DNA, and the rest consists of genes. A current British project uses the genome of the puffer fish (Fugu) to bring more clarity into the distinction between relevant gene-related DNA and irrelevant information. This fish has only ~400 million base pairs, and not ~3 billion as humans, and one can surmise that it is primarily the ‘junk’ DNA that has been eliminated during evolution rather than the indispensable genes. But even if we are left with ‘only’ approximately 30,000 genes for humans, the puzzling question is how such a small number of genes can act in a concerted manner to fulfill all the necessary functions of life. It has become clear that we must get away from the ‘one-gene’ concept for one function. It is the interplay and crosstalk between many genes, their time-and situation-dependent multifunctionality, and the equilibrium between many simultaneous pathways that determines the outcome. Probably the same holds true if we specifically address some unresolved questions related to mechanisms of toxicity.
