The effect of genic time-factors upon differentiation and growth as seen in some snail shells and plants

There are many indications that the genes of an organism, although present in all cell nuclei, do not all act at the same time during the development of the organism. As differentiation and specialization progress the genes (singly or in groups) must be activated or inactivated. These activated genes must be separated in both time and space, for which reason the “activator” has been termed a genic time-factor. The apparent mechanism of such time-factors is elucidated in the present article by analyses of a number of selected snail shells, which provide a permanent record of the development of the animal. The effect of the time-factors appears to represent shifts in the spectrum of gene activity. Certain genes are switched on or off in much the same way as the activity of the shell chromophores was found to vary. In order to demonstrate such shifts in gene activity a number of chromatographic tests were also carried out. Significant differences were obtained when comparing juvenile and adult phases in certain plant species, including Hedera helix.