ABSTRACT
The collective conversion to Mendelism of the biological community has been described by the historian Garland Allen in the following way: What many workers between 1900 and 1910 failed to grasp was the fundamental distinction between the hereditary particle itself and the recognizable adult character to which it presumably gave rise. This distinction between what is called the genotype and the phenotype was explicitly pointed out in 1911 by the Danish botanist Wilhelm Johannsen. The idea that the cell and every living creature is a duality of genotype and phenotype has become the central concept of modern biology, the most synthetic way of describing anything that lives, the very definition of life. Many protagonists of protein synthesis—aminoacids, messengers, transfers and activating enzymes—are free diffusing molecules in the cell. When a protein is needed, the corresponding gene is switched on, transcription takes place, messengers are translated and a small number of proteins is synthesized.
