150 
GENETICS: A. F. BLAKESLEE 
Proc. N. A. S. 
TABLE 2 
Main Lines and Occurrence of New Globe Mutations from 1915 to 1920. The 
First Mutation Found in 1915 Is Not Included. Under "Type," "P" Stands for 
the Mendewan Character Purple and "W" for White, "ar" for Armed Cap- 
sules and "in" for Inermis, "M" for Many Nodes and "F" for Few Nodes 
NO. 
TYPE 
ORIGIN SEED PARENTS 
NOR. 
Gh. 
% GLOBES 
1 
1 
Par M 
-L ell 1VJL 
Washington, D. C. 
50 
ooio 
O 
U.io I =*= U.UUD 
O 
Z 
w ar ivj. 
Washington, D. C. 
19 
1 9Q9 
q 
o 
War F 
Erfurt, Germany 
9 
854 
A 
Win F 
Erfurt, Germany 
20 
1479 
o 
Par M 
Staten Island, N. Y. 
17 
yoo 
ft 
D 
War M 
vStaten Island, N. Y. 
35 
7 
War M 
VV dl -LVX 
Bronx, N. Y. 
13 
± -LOU 
8 
War M 
Woodbury, N. Y. 
7 
377 
9 
Par M 
Cold Spring Harbor, N. Y 
. 13 
844 
2 
0.236 ± 0.1 12 
10 
Par M 
Charlotte, Va. 
5 
394 
11 
Par M 
Danville, N. C. 
6 
595 
12 
War M 
Lloyds Neck, N. Y. 
1 
92 
13 
War F 
J. L. Childs 
6 
625 
14 
War F 
Naples, Italy 
6 
627 
15 
Par M 
D. Stramoinum gigantea 
5 
408 
16 
Par F 
D. Leicharti 
5 
370 
17 
Win F 
D. Laevis 
5 
701 
18 
Par M 
D. Ferox 
5 
400 
1 
0.249=1=0.168 
19 
War F 
D. Querci folia 
7 
653 
Total 
s — Main Lines Inbred 
234 
16605 
9 
0.054 ±0.012 
Fi's 
159 
7086 
3 
0.042 ±0.016 
Back 
crosses 
57 
2064 
Extractives 
215 
12353 
12 
0.091 ±0.018 
Total 
s — Crosses and Extractives 
431 
21503 
15 
0.070 ±0.012 
Grand totals 
665 
38108 
24 
0.063 ±0.009 
centage of recordable seedlings was obtained when Globes were selfed 
than when they were crossed with normals. 
Simple trisomic mutants produce dimorphic gametes with 12 and 13 
chromosomes instead of gametes with uniformly 12 chromosomes as is 
characteristic of normals. Two types of egg cells should be produced in 
equal numbers and, on the assumption that in general only pollen grains 
with 12 chromosomes are able to assist in fertilization, an equal number of 
Globes and normals should appear in the offspring of Globes. That mu- 
tants and normals are not thrown in equal numbers is probably due to the 
weaker vigor of the mutant zygotes. 
From the foregoing, it is concluded (a) that the mutant complex is trans- 
mitted primarily through the egg cells and (6) is transmitted not at all or 
only to a slight extent through the pollen ; (c) that the deviation in the off- 
spring from an equality of Globes and normals is due to the lessened vital- 
ity of the mutant forms ; id) that the higher percentage of Globes obtained 
by crossing Globes with normals, over selfing, is due to an increased vigor 
brought about by the cross. 
Simple trisomic mutants are characterized by a considerable proportion 
of defective pollen grains. The Globe has about 8 per cent bad grains 
