346 



PERMANENT HYBRIDS 



(Each chromosome is given the initial letter of its complex in 

 the middle to distinguish it. 



The exchange of segment A oi A^B with segment G of F^Gwill 



B b 





^0 



66 (^6 09 QH 



D 



C i\ P 



MIL !_LLL 



AbB-BxC-Cfe-£fF-FxD-Dl)A- 



AB- BC-CE- EG -GH-HF- FD- DA 



Fig. 106. — Pachytene diagrams of pairing in (i) a homozygote ; 

 (2) a simple interchange heterozygote with interstitial segments 

 b and d ; (3) a double interchange heterozygote with differential 

 segment x ; (4) and (5) triple interchange heterozygotes showing 

 two ways in which the differential segments may develop. 

 (D., 1936 rt-) 



give two new chromosome types G^^B and F^A, and a new kind of 

 segregation giving a gamete containing all the necessary 14 segments 

 arranged as follows : 



stihvelans Bf, DE, FA , G^H, K^L, MJSl, OP. 



