Science has been progressing at a fantastic speed this decade. For old timers such as myself, the replacement of paradigms in biology has been intellectually bearable, but only just so. I was born and educated in the era before 1950, when life was the domain of proteins, and I had to adapt myself to a new way of looking at life after the discovery of the double helix and the nature of the genetic code. James Watson and Francis Crickâ€™s seminal paper, in 1953, finally provided the structural and chemical explanation of how cells store, use, and pass on information to daughter cells. This gave rise to the central paradigm in molecular biology: that structural information in the cell flows irreversibly from gene to protein, intrinsic to which is the concept that the sequence of amino acids in a protein entirely governs its final structure. Similarly, what is true for protein synthesis is also true for the mechanisms of heredity: that the genome (the full complement of genes in a cell) controls phenotype (all the characteristics of a living organism).
AdvertisementMore than a half-century later, a large majority of biologists believe that the mechanism postulated by molecular biology is not only true, but the only conceivable system in life. Yet, a small number of researchers have recently discovered provocative anomalies that are threatening this scientific idea. The question then is this: Is the central paradigm of molecular biologyâ€”that all genetic information is stored and transferred digitally through DNAâ€”the only possible explanation of how life evolved, or are there other mechanisms of heredity in living organisms? Evidence is mounting that hereditary information can be transferred in an analogous way through the prion.
Whoa.Â A paradigm shift in molecular biology?