STUDIES ON THE GENETICS OE FLOWER-COLOURS, ETC. 
129 
in F, (35 and 12 magentas produced respectively). The orange and tlie red 
found in addition have probably been produced by tlie “loss-mutation”, but 
as to the mode of production of flesh-coloured plants we are in the same 
position as in respect to Nos. 17 and 18 just cited, and consequently we are 
not able to make any surmise about it. 
V. Change of the Linkage Ratio. In No., 24 we see that one magenta 
ex white-IIx magenta segregates into 28 magentas, 2 reds, 3 oranges and 11 
wliites. We may consider this magenta parent to Lave Lad the composition 
CcJFtrBb, and the appearance of 2 reds which have never been met with in 
.^-generation (with one exception, s. the Table VI, A) is, as I think, due to 
the change of the complete linkage between It and It into a partial, as we 
have seen in the Cross VUI. Suppose that Jt and Jt are linked according 
to the series n : 1:1 : n ; since no such relation exists between C and Jt or 
between C and Jt, we should have the eight following classes of gametes in 
the ratios indicated, viz.:— 
nCJtJt + ncJJB-\-lCrB-\- lev B +-1 CBb 4-1 cJJb y nCrb -f nerb. 
The mating of male and female gametes of such constitutions should give rise 
to the four following kinds of zygotes in the ratios indicated, viz.:— 
Magenta 
Red 
Orange 
White 
9a 3 + l2?i + 6 
6n+3 
3n 3 +6ft-t-3 
4ft 3 + 8ft+4 
Though the number of individuals in No. 24 is rather small, the following 
calculations were made. Since we have observed in the Cross VIII the 
linkage between Jt and B belonging to the series 5 : 1 : 1: 5 or 6 : 1: 1: 6, 
I have put w=5 or 6, and then we have in respect to the expected number 
t 
of individuals for each kind of zygotes. 
Magenta 
Red 
Orange 
White 
Totals 
n = 5 
22-23±3-3 
2-52+1-5 
8-25+2-6 
ll-00±2-9 
44 
ft = 6 
22-56±3-3 
2-19±l-4 
8-25+2-6 
ll-00±2-9 
44 
Actual 
28 
2 
3 
11 
44 
