GENES IN RELATED SPECIES 103 



as in the case of D. melanogaster, and D. simulans, there 

 may always remain some doubt as to their identity, be- 

 cause similar mutant types that are not identical are 



n nr lY ¥ 



62.0 -|-P 



^«° + 8^ ^, St K Ac 



42.0 



0.3 



00": 



50 



6 0' 

 H5, 

 16.0 • 



V 



Sn 

 m 

 24.0 + r 



36 

 420 



865 

 10-] .0 



.sc 



ro 



fu 

 CO 



as 

 si 



8 



Cf Tm 



^0 Sb 



bx 



8P 

 M 





v^(\ 



D. b s c u ra 



Ms 



Fig. 61. 



Chart of the location of the mutant genes in the chromosomes of 

 Drosophila obscura. The loci corresponding with those of D. 

 melanogaster are sc=zscute, y=yellow, No2=:Notch, wh=:white. 

 (After Lancefield.) 



