Gates: On the Nature of Mutations 



101 



AN EARLY DISCOVERED MUTANT 



Rosette or young seedling of Oenothera lata, a mutant from Oenothera lamarckiana 

 (shown in fig. 1), which was discovered by De Vries as early as 1887. Even the 

 youngest leaves have broad, rounded tips, in contrast to the more pointed ones of 

 the parent form, and the leaves are also more crinkled. It has been shown that the 

 cells of this plant contain an extra chromosome not present in those of the parent, 

 and it is this, apparently, which determines the nature of this mutant. (Fig. 2.) 



quarters that Oenothera lamarckiana 

 was a "hybrid," although it has usually 

 not been stated in just what sense this 

 term was used. More recently all 

 Oenotheras have been stigmatized as 

 hybrids, and the conception has even 

 been extended to the whole family of 

 Onagraceae. It seems that this is the 

 fate of all organisms which come to be 

 intensively studied from the genetic 

 point of view. 



Having regard to the facts, it is not 



necessary to suppose that any recognized 

 species of Oenothera is a hybrid in the 

 sense of having been synthesized directly 

 through crossing between two other 

 species. An extraordinary flaw in all 

 the reasoning in this subject has been 

 the tacit assumption that if any plant 

 could be shown to be a "hybrid" then 

 any mutations it might produce must 

 be a result of that condition. But it is 

 necessary to point out that even if the 

 assumption that all Oenotheras are 



