Chromosomes and Genes 191 



does not the whole molecule react and not its loci? (I repeat that this 

 is meant as a simile. I certainly do not intend to enter upon a chemi- 

 cal discussion on the relation of visible or active properties of a sub- 

 stance to its molecular constitution.) 



At this point another argument may be added. It is a necessary 

 corollary of the theory of the gene that there must be an evolution of 

 genes. (See also the chapter on evolution.) A man should certainly 

 have more genes than an amoeba, and therefore a chromosomal 

 phylogeny paralleling an increase in the number of genes should be 

 apparent. Actually, the pattern, size, and number of chromosomes 

 have not changed from protozoa to man. The chromosome comple- 

 ment of some gregarines and relatives, or flagellates, looks exactly like 

 that of higher animals. The size and length of the chromosomes, their 

 intimate structure, behavior in synapsis, and so on are exactly the 

 same as in higher forms. Thus they should contain a similar number 

 of genes. A popular way out of this dilemma would be to say that 

 these protozoan chromosomes contain much inert material. We have 

 already discounted the idea of inert material. Here the only expla- 

 nation for the preponderance of inert material would be that its 

 function is to keep room in the chromosome for future evolution of 

 new genes! Another way out would be to say that it is not the number 

 of genes which is different but their ability to produce more and more 

 complicated products. This would not agree with the fact that typical 

 products of genie action like vitamins, enzymes, and sterols are more 

 or less alike in all living organisms. I cannot see any way out of this 

 diflBculty except the assumption that the evolutionary process within 

 the chromosome means an increase of the diversification within the 

 hierarchical pattern adding more and more chances for permutation 

 within the whole. ( We shall return to this subject in the short chapter 

 on evolution.) 



It might seem to some diehards that all these discussions are 

 exercises in semantics without any relation to the facts. This is not so, 

 however. The discovery of position effect, of genie actions in the 

 absence of assumed genes (position effect of deficiencies), of visible, 

 relatively large segments of allelism and their overlapping (i.e., 

 variable delineation) force us to re-examine the fundamentals of 

 classic genetics, and we find that they do not suffice for an explanation 

 of these discoveries. Therefore, we must try to develop broader ideas 

 which describe the facts not only in a different terminology but with 

 a basically different mental attitude. In this new way of looking at 

 fundamentals, the atomistic view of collaborating independent units is 



