Anomalous Endosperm Development in Maize and the Problem of Bud Sports. 253 



resulted in the anomalous seed now under discussion. If linkage could 

 be demonstrated between two factors both of which were in a simplex 

 condition, there would be no fundamental difference between this case 

 and the cases previously discussed. With the other seeds only a single 

 one of the independent, heterozygous factors could have segregated. 

 Here two linked factors might have behaved as a single factor so far 

 as segregation is concerned. That is, a single chromosome bearing both 

 factors might have gone without division to one daughter cell. Since 

 both H and I — if, as seems likely, the latter was present — were carried 

 by the second male nucleus and neither one by the polar nuclei, both 

 must have been in the simplex condition. But since they are not linked, 

 it seems probable that more than one chromosome must have been 

 concerned in any segregation that may have brought about the observed 

 result. 



And if it be assumed that I was not present, the case is even 

 less simple. Both C and R must have been present in both polar nuclei 

 and therefore have been in duplex condition in the endosperm cells. 

 The loss of two C or two R factors would then have been necessary 

 in order to change colored to colorless aleurone. Moreover, since H 

 was carried by the second male nucleus, and could not, therefore, have 

 been in the same chromosome with either (J or R, at least three factors 

 must have been included in any segregation that could have produced 

 the observed result. Two C or two R chromosomes must have 

 gone undivided to one daughter cell and one H chromosome to 

 the other. 



Another difficulty here is that the color change was probably from 

 colorless to colored rather than from colored to colorless. This is 

 suggested hy the fact that a large part of the seed was white and 

 only a small part colored. Tliis, together with the fact that the presence 

 of I was indicated by the almost wholly colorless seeds of the ear on 

 which the anomalous seed was found, makes the previous assumption 

 of a segregation including two chromosomes, one with H and one with I, 

 appear the more reasonable of the two. 



It remains to be shown how tliis anomalous seed can be inter- 

 preted in accordance with the hypothesis of somatic mutation. Let us 

 first assume that no inhibitor of aleurone color was present in the 

 wMte seeded parent. The fertilized endosperm nucleus must then have 

 been CCcRRrHhh, or either C or R but not both may have been homo- 

 zygous. Such endosperm should be colored and horny throughout. In 



