COBB AND BARTLETT: INHERITANCE IN OENOTHERA 



477 



one modification in common, there are additional modifications 

 in the cases of all except mut. formosa which are peculiar to each 

 mutation. 



If the a. gamete of Lexington C were to undergo exactly the 

 same modification that in Lexington E brings about the pro- 

 duction of a particular revolute-leaved mutation, the effect, as 

 far as revoluteness is concerned, would be nullified by the factor 

 pair for flatness in one of the pairs of freely segregating chromo- 

 somes. This factor pair has not yet become spontaneously 

 heterozygous, and consequently no other strain except Lexington 

 K has thrown revolute-leaved mutations. 



Let a represent the nondissociating, characteristic portion of 

 the a gamete, bearing a factor for flatness, and susceptible of 

 mutative modification to a', in which the factor for flatness is in- 

 operative. Then using the usual Mendelian notation for the 

 freely segregating factor pair for flatness (FF = homozygous flat ; 

 ff = homozygous revolute) the constitution, phaenotype, and be- 

 havior of the various forms and hybrids involved in our ex- 

 periments would be as follows: 



f. typica C, \ 



mut. latifolia C, \ a 



mut. gynocrates C, 

 f. typica E, 

 mut. formosa E, 

 typica E X formosa E, 

 formosa E X typica E, 



flat, and, with respect to this 

 jSFF, character, immutable. 



typica C X formosa E, Fi, a/SFf, 



typica C X formosa E, F2, 



formosa E X latifolia C, Fi 



formosa E X latifolia C, F2 



a!|Sff, flat, mutable. 



a'^E, revolute. 



ajSff, flat, mutable. 



a'jSff, revolute, breeding true with re- 

 spect to this character, 

 flat, segregating with respect to 

 mutability. 



1 ajSFF, flat, immutable, breeding true. 



2 a/SFf, flat, continuing the segregation 

 I of the Fi. 



I a/Sff, flat, mutable, otherwise breeding 



true. 



a'/3Ff, flat, segregating with respect to 

 revoluteness. 

 [ la'jSFF, flat, non-segregating. 

 I 2a' ^Vi flat, continuing the segregation 



oftheFi. 

 [ la'/Sff revolute, breeding true. 



