314 



INHERITED LINKAGE VARIATIONS 



Numerous other tests have been made of the right end of the Nova 

 Scotia chromosome. Table 9 gives a list of the different cross-overs 

 tested, together with the cultures derived from those sources. In 

 addition, there are a number of cultures (including all those in which 

 the character star was tested) in which the origin of the C H r segment 

 is uncertain, because it has been passed through females homozygous 

 for CUT from different sources (see below). 



TABLE 9. Tests of right-hand end of Nova Scotia chromosome. 



These cultures all contain only that part of the Nova Scotia chromo- 

 some that lies to the right of a point between black and curved (171 

 series), purple and vestigial (two 524 N series), or purple and curved 

 (685 series). Since they all agree in the results produced, we may 

 conclude that the gene responsible for these results is located some- 

 where to the right of purple. In dealing with the original Nova 

 Scotia chromosome we found that removal of the speck end made no 

 difference in the ratios given. It was therefore to be expected that 

 the right-hand piece would show the same relation, i. e., that C Ur 

 is between purple and speck. The following data show that such is, 

 in fact, the case. 



Culture 546, of the second 524 N series, contained a female of the 



r , mated to black purple arc speck males. 



constitution 



a r s. 



By double crossing-over, a female was produced of the constitution 



- - . This female, in which the extreme speck end of the 

 b p r a r s p 



old Nova Scotia chromosome had been lost, was mated to black purple 

 vestigial arc speck males, in culture 570. All later cultures of the 

 second 524 N series received their C// r from this female. They gave 

 essentially the same results as the other C// r cultures, and have 

 therefore been included in tables 10 and 11. The fourth line of 

 figure 1 represents a map based on table 11. 



