2 /hif/n^ ffe/aflOns/upS (2 chromosomes) 

 (a)/ cAiasma <►■<» 



(h) 2 chiasmafa 



X 



H 



3 Pairing /felafionships. (2e/tiasmah) 

 (c) 2 chromosamea 



(d) d chromosontes 



/4 



Fig. 146. — Diagram to show how terminal affinity will preserve 

 terminal association with terminalisation of chiasmata having different 

 relationships. The genetic interpretation follows the chiasmatype 

 hypothesis. Left, before fusion of chiasmata ; right, after fusion. If 

 the end particles had not both lateral and terminal affinity the second 

 type would give failure of pairing owing to its chiasmata being com- 

 pensating. The dotted lines indicate the affinities that are satisfied 

 after terminalisation. 



