No. 499] A NEW MENDELIAN EATIO 437 



mottled offspring would be produced by every purple- 

 mottled parent, and there would be no equality between 

 the purple-mottled and black in many families of the 

 third and subsequent generations ; but those F 3 families 

 which have been thus far investigated show a number 

 of instances in which purple mottled parents produce 

 no brown or brown mottled young and there is a con- 

 tinued equality between the mottled and self-colored 

 offspring of such parents. The remaining possi- 

 bility, namely, that individuals which carry the mottled 

 pattern, M, but are homozygous with respect to that char- 

 acter, are not mottled but self-colored, is the only one that 

 fits all of the observed facts. The mottled color-pattern 

 must be heterozygous in order to become apparent in the 

 hybrids. 



We may then indicate the composition of the group of 

 individuals of F 2 which carry the dominant mottling fac- 

 tor, M, and the expectation as to the composition of the 

 offspring which each will produce in F 3 as follows : 



1 PBMPBM == B1(B1) (M latent in all). 



2 PI/P#m==PM(lPM:lBl) (M latent in ^ the Bl). 

 2 PBMPbM = Bl(3Bl:lBr) (M latent in all). 



2 PBMpBM = B1(3B1:1W) (M latent in all). 



4 PBMPbm -- = PM(3PM : 3B1 : IBrM : IBr) (M latent 

 in 4 the self-colored). 



4 PBMpBm = = PM(3PM : 3B1 : 2W) (M latent in the 

 Bl and f the W). 



4 PBMpbM =Bl(9Bl:3Br:4W) (M latent in all). 



8 PBMpbm = PM(9PM:9Bl:3BrM:3Br:8W) (M la- 

 tent in -J the self-colored and f the 

 W). 



It will be seen from this scheme that the mottled color- 

 pattern could exist and does exist as a latent (i. e., in- 

 visible) character in pigmented beans just as well as in 

 the white bean, which is contrary to the assumption made, 

 when I insisted that the mottled pattern must have come 

 from the white bean. It is also obvious that the mottled 



