6. Tests of miscellaneous genes with chromosome-1 markers - Twelve genes, whose linkage had not been previously determined, have been tested with several chromosome-1 markers. Tests of some of these were reported last year (N. L. 1940, p. 18) with only one clear indication of linkage, namely, bm2 with v19. The data given in the accompanying table were obtained from F2 cultures of last summer. Percentages of recombination have been calculated with the help of Immer's tables. Many of the relatively large deviations from 50 per cent are not statistically significant. Percentages that show significant deviations from 50, or deviations on the border line of significance, are accompanied by their respective probable errors. The tests of this year are inadequate for much of the short arm of chromosome 1, since, except for sr, the markers used are all in the long arm.

The frequency arrays for bm2 and v19 from last year's report and from records of last summer are:

 

+   bm2   ++ bm2+ +v19 bm2 v19 Total
v19  +  
 
N. L. 1940, p.19   42 25 21 0 88
New cultures   60 42 37 6 145
 
Total   102 67 58 6 233

 

Recombination percentage = 16 4.3

 

It seems clear that v19 is in chromosome 1. Attempted tests with fs have failed. It is not known, therefore, whether v19 is to the left or the right of bm2.

 

Tests of non-linked genes

 

Chromosome-1 markers

 

New genes sr ms17 br f an gs bm2
 
at 58 - 49 54 52 43 42
bm3 50 - 57 48 57 41 -
g2 51 - 40 46 46 364.5 343.7
ms5 60+ - 384.2 47 37 41 53
ms6 55 - 41 41 345.9 35 42
ms9 36 - 327.1 - - - -
ms10 - - 47 374.9 44 - 52
ms13 53 - 46 49 49 60+ -
ms14 - - 414.2 414.2 404.3 49  
na2 48 55 - - 38 40 -
yg3 46 - 47 47 38 - 38
v19 42 - 44 55 38 - 235.3
*v19 - P52 58 - 51 - <19

*From N. L. 1940, p. 18

 

R. A. Emerson