CHAPTER VII 
THE CORRESPONDENCE BETWEEN THE 
DISTRIBUTION OF THE CHROMOSOMES 
AND OF THE GENETIC FACTORS 
Attention has been called to the fact that paired 
factors are distributed in the same way as are 
homologous chromosomes, and that factors which 
are assorted independently are distributed in the 
same way as non-homologous chromosomes. In 
proof of the latter point there is Wilson’s evidence 
for a Metapodius with three homologous m-chromo- 
somes. It was found that the extra m goes to the 
gamete that receives X as often as to the other 
gamete. Miss Carothers describes in detail several 
‘cases in the spermatogenesis of grasshoppers where 
the distribution of chromosome pairs with unequal 
members shows complete independence between 
pairs. Not only are the pairs of factors assorted 
independently, as are the chromosomes, but in 
Drosophila, where the number of independently 
assorting groups of factors has been determined, it 
has been found that the number is identical with the 
number of chromosome pairs. Moreover, even the 
relative sizes of the groups—both as determined by 
the number of factors they contain and by the fre- 
quency of crossing over within them—are the same 
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