MENDELISM 17 



D[R] R 



• x o § 



• 

 o 



o 

 o 



O X o § 



• X o = 

 O X o 



Law 6 is illustrated in the self-fertilization of hybrids. 

 These laws have been confirmed in several species of 

 plants and animals. 



I must now draw your attention to the fact that 

 dominance is not invariably a feature of either member of 

 a pair of contrasted characters. Sometimes the hybrid 

 differs considerably from both parents. An exceedingly 

 interesting example of this fact has been worked out by 

 Prof. Punnett. He says, " Breeders have long recognized 

 the difficulty of obtaining a pure breed of the Blue 

 Andalusian Fowl. No matter how carefully the blues are 

 selected, they always throw ' wasters ' of two sorts, some 

 pure black, and others of a peculiar white with black 

 splashes. Careful breeding shows that, on an average, one 

 half of the offspring from a pair of blue andalusians come 

 blue, one quarter black, and one quarter white. These 

 numbers at once suggest that the blues are hybrids " (see 

 Law 6). " If this is so, it follows that the blacks and 

 the splashed whites are pure, and ought to breed true. 

 Experiment has shown that such is actually the case. 

 Further, we should expect hybrid offspring from a union of 

 the two pure breeds, the black and the white " (see Law 3). 

 " Here, again, experimental results accord with theory. 

 When a black and a white are bred together, all their 

 offspring, without exception, are blue. The black and the 

 white are pure-breeds, the so-called ' pure blue ' is, and 

 from its nature ever must be, a mongrel. The black and 

 the white are two contrasted characters, and the essential 

 feature of Mendel's theory, ' that the germ-cells remain 



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