CROSSING-OVER WITHOUT REDUCTION 



297 



metaphase and in which failure of reduction is due to suppression of 

 the first (or indeed the second) division should show a very limited 

 amount of segregation. Suppression of the first division will give 



Met. I 



\ / 



TelI 



Te lJ {pesMution) 



Met!?? 



Tel.E 



<- 



-> 



Fig. 98. — Scheme showing how a restitution nucleus will give 

 numerically unreduced gametes showing segregation of differ- 

 ences so long as pairing of dissimilar chromosomes occurs. 



diploid nuclei showing segregation, in respect of the differences 

 between such chromosomes as paired, approaching the proportions 

 1:2:1 asymptotically. Thus, when hybridity reaches the point 

 at which restitution nuclei are formed, segregation is appropriately 



