Part 7
LINKAGE OF VERMILION, BAR, AND FUSED.
Males from the stock of (red) bar fused were mated to vermilion (not-bar, not-fused) females, and produced bar females and vermilion males. The bar F_1 daughters were back-crossed to vermilion fused males and produced the cla.s.ses of offspring shown in table 34.
TABLE 34.--P_1 _vermilion_ [female] [female] _bar fused_ [male] [male].
_B. C. F_1 bar_ [female] _vermilion fused_ [male] [male].
+----------+-------------------+---------------------+------------------+
v
v B' f_u
v f_u
-----------------
----+--------------
-----------+----
B' f_u
B'
Reference.+----------+--------+----------+----------+-----------+------+
Vermilion
Vermilion.
Bar
bar
Wild-type.
Vermilion
Bar.
fused.
fused.
fused.
+----------+----------+--------+----------+----------+-----------+------+
140 I
137
130
35
40
5
8 ~
141 I
144
137
38
41
4
2 ~
142 I
153
120
43
58
6
7
143 I
153
92
44
41
3
7
145 I
69
62
29
19
1
..
146 I
96
103
30
34
7
3
156 I
62
45
25
27
1
4
157 I
93
57
11
31
2
2
+----------+--------+----------+----------+-----------+------+
Total.
907
746
255
291
29
33
+----------+----------+--------+----------+----------+-----------+------+
+--------------------+--------+--------------------------------+
v B'
----+--------+----
Cross-over values.
f_u
+-----------+--------+ +-----------+--------+-----------+
Total.
Vermilion
Fused.
Vermilion
Bar
Vermilion
bar.
bar.
fused.
fused.
+-----------+--------+--------+-----------+--------+-----------+ ~ ..
..
355
21
4
25
~ ..
..
366
22
2
23
1
..
388
26
4
29
3
1
344
26
4
28
1
..
181
27
1
27
..
..
273
23
4
26
..
..
164
32
3
35
..
2
198
22
3
23
+-----------+--------+--------+-----------+--------+-----------+
5
3
2,269
24
3
27
+-----------+--------+--------+-----------+--------+-----------+
The data show that the factor for fused lies about 3 units to the right of bar. This is the furthest point yet obtained to the right. The reasons for locating fused to the right of bar are that, if it occupies such a position, then the double cross-over cla.s.ses (which are expected to be the smallest cla.s.ses) should be vermilion bar and fused, and these are, in fact, the smallest cla.s.ses. The order of factors is, then, vermilion, bar, fused. This order is confirmed by the result that the number of cross-overs between fused and vermilion is greater than that between bar and vermilion.
In order to obtain data to balance viability effects, the following experiment was made:
Vermilion (not-bar) fused males were bred to (red) bar (not-fused) females.
The daughters and sons were bar. The daughters were back-crossed, singly, to vermilion fused males and gave the results shown in table 35. Each female was also transferred to a second culture bottle, so that for each female there are two broods given consecutively (82, 82', etc.) in table 35.
The results given by the two broods of the same female are similar. The values are very near to those given in the last experiment, and confirm the conclusions there drawn. The combined data give the results shown in table 36. {56}
TABLE 35.--_P_1 bar [female] [female] vermilion fused [male] [male]. B.
C. F_1 bar [female] vermilion fused [male] [male]._
A - Vermilion fused.
B - Bar.
C - Vermilion bar.
D - Fused.
E - Vermilion.
F - Bar fused.
G - Vermilion bar fused.
H - Wild type.
-------------------------------------------------------------------------
v f_u
v B'
v
v B' f_u
Cross-
--------
----+----
----+----
-+---+---
over
B'
f_u
B' f_u
Total.
values.
Reference +-------------+---------+---------+---------+ +-----------
A
B
C
D
E
F
G
H
C
F
A ----------+------+------+----+----+----+----+----+----+------+---+---+---
82
165
165
63
57
8
7
1
..
466
26
3
29 82'
104
87
26
24
..
4
..
..
245
20
2
22 83
128
164
51
39
6
4
..
..
392
23
3
26 83'
100
94
28
30
4
4
..
..
260
22
3
25 89
85
105
23
24
5
2
..
..
244
19
3
22 89'
78
91
21
27
1
2
..
1
221
22
2
23 90
86
85
30
28
5
..
..
..
234
25
2
27 90'
33
38
22
14
4
1
..
1
113
33
5
36 91
125
107
41
31
1
1
..
..
306
24
1
24 91'
91
95
31
25
5
1
..
2
250
23
3
25 92
109
136
41
24
4
2
..
..
316
21
2
23 92'
100
105
29
29
..
1
..
1
265
22
1
22 93
75
67
19
20
..
1
..
..
182
21
1
22 93'
68
94
31
17
1
1
..
..
212
23
1
24 94
84
96
31
35
8
1
..
..
255
26
4
29 94'
61
73
20
22
5
4
..
..
185
23
5
28 95
84
102
27
26
3
3
..
..
245
22
2
24 96
144
148
43
34
1
2
..
1
373
21
1
21 97
81
96
25
20
5
3
..
..
230
20
4
23 98
107
112
39
33
1
2
..
..
294
25
1
26 Firsts
1,273
1,383
433
371
47
28
1
1
3,537
23
2
25 Seconds
635
677
208
188
20
18
..
5
1,751
23
3
25 ----------+------+------+----+----+----+----+----+----+------+---+---+--- Total.
1,908
2,060
641
559
67
46
1
6
5,288
23
2.3
25 ----------+------+------+----+----+----+----+----+----+------+---+---+---
TABLE 36.--_Linkage of vermilion, bar, and fused with balanced viability._
+------------+----------+-----------+-----------+-----------+--------+
v B' f_u
v
v B'
v f_u
--------
--+------
-----+---
-+---+---
Total.
B' f_u
f_u
B'
+------------+----------+-----------+-----------+-----------+--------+
5,621
1,756
175
15
7,567
Percentage
74.3
23.19
2.31
0.2
+------------+----------+-----------+-----------+-----------+--------+
Some additional data bearing on the linkage of vermilion and fused were obtained. Males of (red) fused stock were bred to vermilion (not-fused) females, and gave wild-type females and vermilion males, which inbred gave the results shown in table 37.
The percentage of cross-overs between vermilion and fused is here 27, which is in agreement with the 26 per cent of the preceding experiment.
The converse experiment, namely, red (not-fused) females by vermilion fused males also gave, when the wild-type daughters were {57} back-crossed to vermilion fused males, a linkage value of 27 units. Two 10-day broods were reared from each female. The data given in table 38 show that the percentage of crossing-over does not change as the flies get older. The locus of fused on the basis of all of the data is at 59.5.
TABLE 37.--P_1 vermilion [female] [female] fused [male] [male]. F_1 wild-type [female] [female] F_1 vermilion [male] [male].
KEY: A: Non-cross-over [male] [male].
B: Cross-over [male] [male].
C: Females.
D: Vermilion.
E: Fused.
F: Vermilion fused.
G: Wild-type.
H: Total [male] [male].
I: Cross-over values.
+------------+-----+-----------+----------+-----+----+
A
B
+-----+-----+----+-----+
Reference.
C
D
E
F
G
H
I
+------------+-----+-----+-----+----+-----+-----+----+
79 I
299
93
96
37
36
262
28
80 I
245
93
60
28
27
208
26
81 I
263
101
63
22
40
226
27
+-----+-----+-----+----+-----+-----+----+
Total.
807
287
219
87
103
696
27
+------------+-----+-----+-----+----+-----+-----+----+
TABLE 38.--P_1 wild [female] [female] vermilion fused [male] [male]. F_1 wild-type [female] F_1 wild-type [male] [male].
KEY: A: Wild-type [female] [female].
B: Non-Cross-over [male].
C: Cross-over [male].
D: Vermilion fused.
E: Wild-type.
F: Vermilion.
G: Fused.
H: Total [male] [male].
I: Cross-over values.
+------------+-------+------------+-----------+-----+----+
B
C
+-----+------+-----+-----+
Reference.
A
D
E
F
G
H
I
+------------+-------+-----+------+-----+-----+-----+----+
52
96
25
30
16
11
82
33
52'
176
59
64
24
19
166
26
53
60
20
22
9
6
57
26
53'
76
21
27
11
10
69
31
54
88
35
38
14
16
103
29
54'
60
22
20
8
9
59
29
57
61
22
20
7
11
60
30
57'
170
47
54
24
19
144
30
58
128
37
55
14
10
116
21
58'
144
38
64
16
15
133
23
Firsts
433
139
165
60
54
418
27
Seconds
626
187
229
83
72
571
27
+-------+-----+------+-----+-----+-----+----+
Total
1,059
326
394
143
126
989
27
+------------+-------+-----+------+-----+-----+-----+----+
FORKED.
On November 19, 1912 there appeared in a stock of a double recessive eye-color, vermilion maroon, a few males which showed a novel form of the large bristles (macrochaetae) upon the head and thorax. In this mutation (text-fig. E) the first of several which affect the shape and distribution of the bristles, the macrochaetae, instead of {58} being long, slender, and tapered (see Plate 1, fig. I), are greatly shortened and crinkled as though scorched. The ends are forked or branched, bent sharply, or merely thickened. The bristles which are most distorted are those upon the scutellum, where they are sometimes curled together into b.a.l.l.s.
LINKAGE OF VERMILION AND FORKED.
[Ill.u.s.tration: FIG. E.--Forked bristles.]
Since forked arose in vermilion stock, the double recessive for these two s.e.x-linked factors could be used in testing the linkage relations of the mutation. Vermilion forked males were crossed to wild females and gave wild-type males and females, which inbred gave in F_2 the results shown in table 39. Forked reappeared only in the males in the following proportion: not-forked [female], 742; not-forked [male], 346; forked [male], 301. The result shows that the character is a s.e.x-linked recessive.
TABLE 39.--_P_1 wild_ [female] [female] _vermilion-forked_ [male] [male].
_F_1 wild-type_ [female] [female] _F_1 wild-type_ [male] [male].
+----------+----------+----------------+---------------+--------+-------+
Non-cross-over
Cross-over
Wild-type
[male] [male].
[male] [male].
Total
Cross-
Reference.
[female] +--------+-------+-------+-------+ [male]
over
[female].
Ver-
Wild-
Ver-
Forked.
[male].
values.
milion
type.
milion.
forked.
+----------+----------+--------+-------+-------+-------+--------+-------+
9 I
366
113
123
49
41
326
28
11 I
376
116
150
42
31
339
22
+----------+--------+-------+-------+-------+--------+-------+
Total.
742
229
273
91
72
665
25
+----------+----------+--------+-------+-------+-------+--------+-------+
In table 39 vermilion forked and wild-type are non-cross-overs, and vermilion and forked are cross-overs, giving a cross-over value of 25 units. The locus, therefore, is 25 units to the right or to the left of vermilion, that is, either about 58 or 8 units from the yellow locus.
LINKAGE OF CHERRY AND FORKED.
Forked males were crossed to cherry females (cherry has the same locus as white, which is about 1 unit from yellow) and gave wild-type females and cherry males. These gave in F_2 the results shown in table 40. The non-cross-overs (cherry and forked) plus the cross-overs (cherry forked and wild type) divided into the cross-overs give a cross-over value of 46 units, which shows that the locus lies to the right of vermilion, because if it had been to the left, the value would have been 8 (_i. e._, 33-25) instead of 33+25=58. The difference between 58 {59} and 46 is due to the expected amount of double crossing-over. In fact, for a distance as long as 58 an almost independent behavior of linked gens is to be expected.
TABLE 40.--_P_{1} cherry_ [female] [female] _forked_ [male] [male].
_F_{1} wild-type_ [female] [female] _F_{1} cherry_ [male] [male].
+----------+--------------+---------------+-------------+-------+-------+
Reference.
Females.
Non-cross-over
Cross-over
[male] [male].
[male] [male]
Total
Cross-
+-------+------+-------+-------+-------+-----+[male]
over
Cherry.
Wild-
Cherry.
Forked.
Cherry
Wild-
[male].
values.
type.
forked.
type.
+----------+-------+------+-------+-------+-------+-----+-------+-------+
25
129
145
73
70
65
68
276
48
25'
167
148
74
82
66
88
310
50
36
96
88
52
52
35
51
190
45
36'
57
76
41
32
24
30
127
43
84
76
86
40
34
38
26
138
46
84'
62
71
24
39
25
28
116
46
85
114
86
43
78
41
53
215
44
85'
98
95
48
63
52
46
209
47
86
307
323
152
144
118
165
579
49
87
351
341
183
213
160
147
703
45
88
244
246
142
142
107
104
495
43
+----------+-------+------+-------+-------+-------+-----+-------+-------+
Total.
1,701
1,705
872
949
731
806
3,358
46
+----------+-------+------+-------+-------+-------+-----+-------+-------+
