INDEPENDENT MENDELIAN INHERITANCE 83 
white. When the endosperm segregation into starchy and sweet is taken 
into account in the same hybrid the segregation will be in the ratio of 
3 starchy:1 sweet in each of these classes, for these characters segregate 
independently of the aleurone color. This gives, therefore, 3 purple 
(8 starchy :1 sweet):1 white (3 starchy:1 sweet) which becomes on 
expansion 9 purple starchy :3 purple sweet :3 white starchy ;1 white 
sweet. 
The correlation of the above facts with chromosome behavior is 
again very simple. The factors W and w le in identical positions in one 
pair of chromosomes and the factors S and s lie in identical positions in a 
different pair of chromosomes. If the difference between the two varie- 
ties of maize is only in these factors, then all the other pairs of chro- 
mosomes in the varieties bear the same set of factors. Accordingly of 
the ten pairs of chromosomes of maize only those two need be considered 
Fig. 39.—Chromosome behavior in reduction in Fi from a cross between purple 
sweet and white starchy corn. Factor symbols: w=white, W = purple, s = sweet, 
S = starchy. 
which bear the above factors. The relations then are shown diagrammat- 
ically in Fig. 39. The parents in both cases produce gametes which are . 
all alike. The crossing of these parents produces a zygote in which two 
pairs of the chromosomes differ in their factor content. One member 
of one pair bears W and the other w and in the other pair one member 
bears S and the other s. Two types of Fy; reduction division are 
possible and these give four kinds of gametes as shown in the diagram. 
Since this has occurred in the formation of both ovules and pollen grains, 
in the self-fertilization of such a plant there are sixteen possible combina- 
tions of gametes, which distribute themselves in four phenotypes in the 
ratio 9 purple starchy:3 purple sweet:3 white starchy: 1 white sweet. 
This feature of the case has already been discussed fully and need not be 
repeated here. 
The actual Peeerene of this analysis with experimental results 
has been shown by several investigators but particularly by East and 
Hayes. In one case they crossed a white flint corn, Rhode Island White 
Cap, with a purple sweet corn, Black Mexican. The F; grains were 
purple starchy and in F: there was sharp segregation for purple and white 
aleurone and starchy and sweet endosperm. In some cases splashed 
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