The Gene Material as the Initiator and the Organizing Basis of Life

Outstanding nineteenth and twentieth century developments in the evidence, conceptions, and speculations concerning the origin and basis of life are considered, with special reference to whether primacy in these respects should be attributed to some form of "protoplasm" in general, or of "gene material," or whether neither of these should be considered to have primacy over the other. The author's view, of the gene material's having primacy (first expressed definitively in 1926), is defended. According to this (as it may today be stated), any living thing, stripped of all its nonessentials, must only have (or have forebears which had) the following three faculties: (1) that whereby it can form more bodies after its own pattern; (2) that whereby, in this process, changes, even indefinitely cumulative ones, can occur, which nevertheless allow the changed successors to form more bodies of these still newer types; and (3) that whereby these different kinds of successors can differently and significantly affect (or be affected by) materials or conditions other than their own, and can thus (when in given surroundings) possess different possibilities for the continuance and extension of their own or still later successor types. Anything having the above three faculties and the external facilities and conditions for exercising them will possess the potentiality of almost unlimited evolution by natural selection. The gene material, it is argued, has these faculties; and primitive conditions afforded it enough means of exercising them to allow it to evolve protoplasm that served it. That is, those descendants of it must have prevailed that altered other materials so as to form them into a surrounding, accessory system, which with increasing effectiveness fostered the self-reproduction of that gene material. In so doing, the accessory system would also be led to foster, under the control of the gene material, the formation, through metabolic processes, of correspondingly more of its own organization. Thus the gene material itself has the properties of life. This may be epitomized by saying that the criterion for a type of thing that has life is whether or not it has the potentiality, at least under some circumstances, of evolution by Darwinian natural selection. (The words in italics, alone, form a simpler statement.) The great modern findings concerning the chemical structure and workings of the nucleic acids and of other material of organisms, as well as findings concerning prebiotic possibilities of synthesis of organic materials, are held to strongly substantiate the above concepts. Included here is the concept of the uniqueness of structure of gene material, since even in diverse cytoplasmic structures (including invaders) having these properties, nucleic acid has been found to be present. It is pointed out, however, that these modern findings also raise certain new, great, and difficult problems (as yet not widely enough recognized to be such). Two of these are herein discussed at some length. One is concerned with how the protoplasmic organization common to all cellular organisms, with its complicated circularity of gene-protein production, evolved. The other deals with how the gene material itself became further organized and stabilized until the enormous genes of higher forms were achieved. Research directed toward the solution of these two questions is urgently needed.