Anomalous Endosperm Development in llaize and the Problem ot Bud Sports. 25ö 



with a small patch of colored, waxy endosperm, in short, just sucli a 

 seed as described by Collins. 



There are still involved what may perhaps be regarded as two 

 mutations since two genetic factors are concerned. It must be recalled 

 in tliis connection tliat H and I are ajipareiitly not the factors whose 

 linkage in inheritance results in the correlation between aleurone color 

 and texture of the endosperm noted by Collins (1). I have elsewhere 

 [Emerson (11)] discussed the possibility of the simultaneous modification 

 of distinct though linked factors while the same factors in the homo- 

 logous chromosome are unaffected. In the present ease, however, the 

 mutation, if one occurred, apparently affected non-Linked factors, that 

 is, factors of two distinct chromosomes. 



Bud Sports. 



On the whole, it seems quite as likely tiiat lialf-and-half seeds of 

 maize may in general be due to somatic mutations as that they may 

 come from somatic segregations: and in this respect they seem closely 

 related to bud sports. In their proposal of the vegetative-segregation 

 hypothesis. East and Hayes (9) indicated a belief that bud sports in 

 general are due to a segregation of factors. My own notion, on the 

 other hand, has been that bud sports are somatic mutations, fundamen- 

 tally the same as seminal mutations. I have supposed them to be due 

 to some real change in genetic factors — the outright gain of at least one 

 new factor, the loss of a factor, or the permanent modification of a 

 factor. In an earlier paper (Emerson (10)), I have pointed out that 

 what appear as seed sports nmy, in some cases at least, have originated 

 as bud sports. 



There seems to be at tendency at present among students of genetics 

 to limit the term mutation to genetic changes other than those associated 

 with Mendelian segregation, as witness the attempt of Davis (5) to 

 throw out certain Oenothera "mutations"' because of the possible hybrid 

 nature of their parent, 0. Lamarckiana. With this attempt to restrict 

 the meaning of the terra mutation, I am wholly in accord. But of 

 course no quarrel over the use of terms can have any bearing upon the 

 question of the real nature of bud sports or of anomalous maize seeds. 

 It follows merely that, if these phenomena are ever shown positively 

 to be due to segregation of genetic factors, those of us who insist upon 

 thus restricting the meaning of the term mutation must refrain from 

 speaking of bud sports as somatic or vegetative mutations. 



