256 



BREEDING 





Doncaster has since found tliat tlie result of crossing 

 pure wild grossulariata $ with cj lacticolor is precisely 

 the same as that of mating No. 4 on p. 252 ; that is, 

 as the result of crossing Fl grossulariata with <S 

 lacticolor. This proves that the wild grossulariata 

 female is heterozygous in regard to this character, 

 half her germ- cells bearing the grossulariata factor, 

 the other half the lacticolor factor. 



Here, then, is an instance in which the simplest 

 interpretation of the phenomena is the supposition 

 that the female is heterozygous for sex, femaleness 

 being the dominant character, whilst the male is 

 pure recessive. The value of this case as evidence 

 for the theory that the female is a hybrid in respect 

 of sex and the male is pure recessive does not merely 

 lie in the fact that this is the simplest way of account- 

 ing for the facts ; for this is also the simplest way of 

 accounting for the fact that males and females are 

 produced in equal numbers in the human species, 



