296 



THE SECOND-CHROMOSOME GROUP 



CHROMOSOME CARRYING DACHSOID. 



The four cultures above noted (table 139) all gave both male and 

 female dachsoids, thus showing at once that the gene is not in the X 

 chromosome. The mothers of all four were heterozygous for sepia, 

 spineless, kidney, sooty, and rough characters that cover practically 

 the whole length of the third chromosome, and the same was true of 

 several later cultures that also gave dachsoid. The dachsoid char- 

 acter was distributed quite at random with respect to these third- 

 chromosome characters, showing that the gene is not in the third 

 chromosome. 



TEXT-FIGURE 86. Dachsoid venation. 860 shows the small size of the fly, with the wing pos- 

 ture; 866 shows a typical wing. 



An F 3 from a cross between speck and a fly that proved to be heter- 

 ozygous for dachsoid produced 15 dachsoid, but unfortunately the 

 speck character was not examined (2859, A. H. S.). 



An F 3 pair (2926) gave a total of 40 flies, of which 4 were dachsoid, 

 26 speck, 10 wild-type, and none dachsoid speck. The count was 

 aberrant in that there were far too few wild-type offspring; but the 



