342 LOCK : STUDIES IN PLANT BREEDING 
albino mice contain some colour in a latent condition ; those 
with which he worked were represented by the following 
44 formulae ” of heredity ” :— 
Homozygotes AG ; AN ; AJ. 
Heteorozygotes AG AN ; AG AJ : AN AJ. 
In the visible expression of the colours (when C is present) 
yellow is dominant over grey and over black, and grey is 
dominant over black. This being the case, Cuénot finds that 
Mendel’s Law is rigidly followed in the formation of the 
gametes. 
Cuénot gives the following example, being one of three 
possible methods by which all three colours yellow, gray, and 
black, as well as albino, can appear in the offspring of a single 
pair :— 
Parents : AG (alb). AN (alb) ON (black) AJ (alb) 
F x AG. AN (albinos)* CN AJ (yellow) 
Gametes AG AN CN AJ CT AN 
4 albinos 
2 yellow 
^ 1 black 
j 1 gray 
I 
i 
J 
The actual numbers obtained in F 2 were— 
81 albinos, 34 yellow, 20 black, 16 gray, the expectation being— 
76 : 38 : 19 : 19 
These observations of Cuénot’s indicate a very important step 
in advance, for they show that an individual, apparently 
recessive in character, may contain a dominant allelomorph in 
the latent state ; and that this may fail to appear even on 
crossing different strains of récessives (a process frequently 
accompanied by the appearance of a previously latent charac¬ 
ter). Yet, at the same time, Mendel’s Law may be strictly 
AG CN 
AN CN 
AG AJ 
AG AN 
AN AJ 
AN AN 
CJ AG 
CJ AN 
gray 
black 
albinos 
yellow 
