5. Linkage data from 3 point back crosses :-

Genetic constitution Regions Total
0 1 2 1, 2
           
+    +   + * 79 - 70
149		 20 - 15
35
15.8%		 42 - 33
75
30.8%		 6 - 1
7		 266
pr  ys   v2
           
bm1  +   + 81 - 87
167		 13 - 21 16.8% 6 - 5
11
6.1%		 1 - 1
2		 214
+   pr  ys
           
+   +   + 118 - 79
197		 21 - 21
42
17.8%		 11 - 10
21
9.8%		 0 - 5
5		 265
bm1 pr  ys
(also seg.
v2 3:1)
           
+   +  Ch 61 - 45
106		 39 - 52
91
46%		 59 - 54
103
49%		 43 - 44
87		 387
bm1 yg1 ch
No linkage
           
+  T5-7a bn 36 - 40
76		 6 - 1
7
10.5%		 2 - 8
10
12.6%		 0 - 2
2		 95
(bn-gl1 18%)
gl1  +    Bn
           
T5-7a  +  + 142 - 72
214		 30 - 51
81
25.5%		 12 - 31
43
14.5%		 5 - 2
7
2.0%		 345
+     gl1  v5
           
+  +   T5-7a 107 - 74
181		 4 - 3
7
4.0%		 39 - 42
81
31.0%		 3 - 1
4		 273
ra gl1   +
           
T1-7  +   + 292 - 201
493		 6 - 7
13
2.6%		 20 - 25
45
8.3%		 1 - 0
1		 552
+    gl1  ij

* v2 classification was not entirely satisfactory.

6. Notes on the above data :

The linkage of T4-5a with yg1 is the first found for yg1. If it is in chromosome 5 it must be out in region where v2 is or even nearer the end. Of course it may be in chromosome 4. The break in each chromosome was near the subterminal knob. The data on chromosome 7 are mostly from interchanges. In T5-7a both breaks were near the subterminal knobs, while in T1-7 the break in 7 was on the long arm not far from the spindle fiber insertion. The data indicate that Bn is out toward the end of the long arm, with ra near the break in 1-7 and gl1 in between. Vp2 apparently is on the bm1 side of pr.