Evolution and Genie Action 491 



part but the entire plant is affected extremely. An especially good 

 example in plants has been studied by Gustafsson (1954) and D. von 

 Wettstein (1954). In golden barley erectoides, a single mutant step, 

 led to drastic change in morphology and anatomy, an altered ecolog- 

 ical response, the origin of a sterility barrier, and (in one case) a 

 new karyotype distinguishable cytologically. Further, these mutants 

 form a basis for a new polymorphy, since secondary mutants appear 

 rather frequently in outcrosses (Hagberg, 1954). Though Gustafsson 

 is not yet ready to follow me completely in my conclusions upon 

 macroevolution, he meets me at least halfway. In Drosophila the 

 homoeotic mutants are examples; in the guinea pig, the poly dactyl 

 monsters (Wright, 1934); and in the mouse, mutants like luxated (see 

 Griineberg, 1952), in which early embryonic determination is shifted 

 in regard to the location of some processes, with effects, such as 

 change of vertebral number, which can be considered as models for 

 known macroevolutionary features ( see Forsthoef el, 1953 ) . Thus there 

 can be no doubt that single mutants can produce new effects upon 

 embryonic determinative processes, leading to great departures in a 

 direction which under proper conditions would lead to macro- 

 evolutionary divergence, especially so when the embryonic power of 

 regulative integration fits the new structure harmoniously into the 

 whole without need for special selective modification. If simple mu- 

 tants can have an avalanche of consequences, a major repatterning of 

 the genie material, as contemplated in the hypothesis of systemic 

 mutation, could produce immense changes in one or a few steps. 

 There is nothing in this idea which cannot be derived in an orderly 

 way from the known facts of chromosomal evolution and the newer 

 theory of the constitution and action of the genie material. It is there- 

 fore to be regretted that Dobzhansky called this point of view a 

 cataclysmic theory, a designation which Stebbins even used for the 

 title of a paper. There is nothing cataclysmic in a postulated process 

 that occurs or is assumed to occur in a way that requires only known 

 basic processes of chromosomal and genetic behavior. If cataclysms 

 enter this theorizing at all, it is the cataclysm of the orthodox and 

 extreme Neo- Darwinism. 



We have not discussed evolution as such, but only its relation to 

 genetic theory. As a matter of fact, evolution should again be ap- 

 praised in the way I see it on the basis of all the material that has 

 been added since my book of 1940 was written. It would then be seen 

 that the number of evolutionists is increasing who take these views 

 seriously and try to combine them with their own ideas (e.g., S. 



