laughnan: nature of mutations 



11 



offspring from A h -P/A and A b -P /A b -Ec (original Ecuador source) 

 heterozygotes. Again we note that the nco-1 alpha strands con- 

 stitute a significant proportion of the total alpha occurrences 

 and the prominence of co-1 and the absence of co-2 alpha strands 

 are further evidence in support of the aforementioned order 

 of components in the A b -P complexes. The absence of nco-2 deriv- 

 atives (Table 2) from A b -V /A heterozygotes is expected since there is 



Table 2. — Constitutions of Alpha-bearing Strands from A h -P/A Individuals 



Marked with T and sh or with T and et. 



*Here and in the following tables population is expressed in terms of A b -V gametes tested, though, 

 of course, an equivalent number of gametes from the homologue were also scored. 



no evidence to indicate that the type A allele is a complex, let alone 

 that it carries an alpha component. And the rare occurrence of nco-2 

 alpha derivatives from the A b -P/A b -Ec heterozygotes (Table 3) is 

 anticipated, since it is established independently that the A h of 

 Ecuador extraction carries an alpha component that is infrequently 

 isolated as a nonrecombinant. 



One further point may be mentioned here. The occurrence of 

 crossover alpha derivatives from the A b -P /A b -E,c heterozygote indi- 

 cates that these complexes have at least one homologous member in 

 common. Evidence on crossover derivatives from A b -P homozygotes, 

 omitted here because it does not bear on the order of the components, 

 indicates that the members of this complex engage in oblique synap- 

 sis from which it may be concluded that A b -V, like A b , is a duplication 



