L96 



( II M'TER 14 



</ x 



Base 



Base 



5? 



i c 



Base 



S9 



Base 



W 



B ° sc (Individually) 



Base 



W 



F, c 



Base 



Base 



=? 



Base 



So*"' 



Base 



;? 



d" (2) 



(1) is absent if the P, Base chromosome contributed to the P 2 Q 

 contained a recessive lethal 



(2) is absent if the P, + chromosome contributed to the P 2 y 

 contained a recessive lethal 



figure 14-2. The breeding scheme used in the Base technique. 



in hemizygous X-chromosomc loci, that is, 

 X-loci without an allele in the Y chromo- 

 some. The males used are wild-type, hav- 

 ing all normal characteristics including ovoid, 

 dull-red compound eyes. The females have 

 X chromosomes homozygous for Bar eye 

 ( B ) , for apricot eye color ( apr ) , and for 

 two paracentric inversions inside the left 

 arm. The smaller inversion (fnS) lies inside 

 the larger inversion (/// sc s] .sc\ whose left 

 point of breakage is designated sc 81 and right. 



sc 8 ) which includes almost the entire left 

 arm. "Base' 1 derives its name from #ar, 

 apricot, .scute inversion. Stock Base fe- 

 males (or males) have narrow-Bar eyes of 

 apricot color. The genotype of the Base 

 female is written 



sc s1 B InS apr sc 8 sc 8i B InS apr sc s 



A wild-type male is mated with a Base fe- 

 male and the F, daughters obtained are 

 sc 81 B InS apr sc 8 and appear heterozy- 



