TRANSLOCATION I OF DROSOPHILA. 



437 



b and c) with the normal third chromosome map (Fig. I, a). 

 The map length of the left-hand third will be seen to be slightly 

 increased, but the genes between pink and claret are crowded 

 much closer together. There is an apparent lengthening of the 



B 



0.0 T ru 



26.5- 



43.8 

 47-8 



585- 



65.0 



69.5. 

 707 ' 



o.o ru 



26.0 



St 



Ss 



A 

 H 



44.4 



485 



563 

 61.9 



628 



St 

 -P 



SS 

 A 



61.9 

 63-6 

 66.4 



72.3 

 75.8 



o.o m ru 



28.0 



43.7 

 47.5 



54.4 

 59.1, 



st 



SS 



A 

 H 



6L3 



68.5 



-ro 



CO 



ro 



61.3 



66.8 



69.9 



ro 



CO 



91.1 TO 



100.7 



FIG. i. (a) The normal third chromosome map. (b) and (c) Maps of third 

 chromosome homozygous for translocation. (d), (e) and (/) Maps of third chromo- 

 some heterozygous for translocation. 



distance between hairless and ebony, but this distance is so 

 short, and the probable error so large, that the increase is probably 

 not significant. Between ebony and rough, the region where 

 the second chromosome fragment is attached, the per cent, of 

 crossing over is less than one third of the normal value. These 



