THE CREATION OF SPECIES 



Being interpreted, this means that each individual 

 bears within his system and may transmit to his 

 descendants a multitude of characteristics that he 

 gives no evidence of having, and of which he is quite 

 unconscious. This seems paradoxical, but it is matter 

 of demonstration as regards a great variety of traits. 

 A simple illustration drawn from a familiar physical 

 characteristic will illustrate the point. Let us take 

 the matter of the color of eyes. It appears that if a 

 person of a racial or family strain having dark brown 

 or black eyes marries a person with blue eyes, the 

 offspring of the first generation will all have dark 

 eyes. But these dark-eyed individuals, intermarrying, 

 may have a certain proportion of blue-eyed offspring. 

 Thus the tendency to blue eyes was a latent char- 

 acteristic in the dark-eyed individuals of the second 

 generation, though there was nothing to indicate 

 this that even the most searching examination of 

 their eyes by an expert would have revealed. 



Following Mendel, the student of heredity, noting 

 the fact that when black eyes are mated with blue 

 eyes the progeny all have black eyes, names the 

 black-eyed condition as "dominant" or positive and 

 the blue-eyed condition as "recessive," or negative. 

 The essential characteristic of the dominant trait, it 

 will be recalled, is that it seems to override and ob- 

 literate the antagonistic recessive trait in a given 

 generation. But the all-important quality of the re- 

 cessive trait is its capacity to lie dormant and alto- 

 gether indistinguishable in a generation, or often in 

 successive generations, and yet ultimately to re- 

 appear seemingly quite unaffected by its long sup- 

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