SHORTER ARTICLES AND REPORTS 



THE SIMULTANEOUS MODIFICATION OF DISTINCT 

 MENDELIAN FACTORS 



In another paper 1 on the inheritance of a recurring somatic 

 variation in variegated ears of maize, it was shown that the 

 amount of red color developed in the pericarp of variegated 

 seeds bears a definite relation to the development of color in the 

 progeny of such seeds. The relation is such that the more color 

 there is in the pericarp of the seeds planted the more likely are 

 they to produce plants with wholly self-red ears and correspond- 

 ingly the less likely to produce plants with variegated ears. 

 Self-red ears thus produced behave just as if they were hybrids 

 between self-red and variegated races or self-red and white races, 

 the behavior in any given case depending upon whether the 

 parent variegated ears were homozygous or heterozygous for 

 variegated pericarp and whether they were self-pollinated or 

 crossed with white. 



To interpret these facts I have suggested that perhaps (1) a 

 Mendelian factor for variegation, V, is changed to a self-color 

 factor, S, in a somatic cell, (2) that all pericarp cells directly 

 descended from this modified cell develop red color, and (3) 

 that of the gametes arising from modified cells one half carry 

 the 8 factor and one half the V factor. 2 Whether it ever hap- 

 pens that more than one half of such gametes carry 8 is un- 

 known, but it is certain that a considerable part of them carry V. 

 This is shown by the fact that self-red seeds from a variegated 

 ear that has been cross-pollinated by white-eared maize produce 

 a considerable percentage of variegated-eared plants. Evidently 

 in such cases the duplex condition of the factors is changed to 

 the simplex condition by the change of one V factor to an S 

 factor, so that the zygotic formula VV becomes VS. 



Now it often happens that a considerable patch of self-red 

 grains occurs on an otherwise variegated ear. The cob imme- 

 diately beneath such a patch is sometimes variegated, just like 



'This hypothesis was noted in my discussion of the possible origin of 



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