THE LAWS OF HEREDITY 



self and distributes its representatives in the 

 germ-cells of the next generation quite as freely 

 as does the dominant factor. So there is an even 

 chance that factors of the subordinate type will 

 be represented in the germ-cells that are to pro- 

 duce progeny of a second generation. 



According to the mere theory of chances, if we 

 mix together indiscriminately a quantity of black 

 factors and white factors in equal numbers, and 

 pick out pairs of factors at random, it must result 

 that in any average group of four pairs we shall 

 find one pair of black factors, one pair of white 

 factors, and two pairs of mixed factors. 



If you will experiment with checker-men, draw- 

 ing them in pairs from a mixed lot, you will be 

 surprised to find how generally you approximate 

 the formula, even when small numbers are in 

 question. 



NATURE'S GAME OF CHANCE 



According to Mendel's interpretation, nature 

 performs such an experiment whenever two germ- 

 cells bearing antagonistic factors have come to- 

 gether, and the results of her game of chance are 

 seen in the phenomena of what have come to be 

 spoken of as Mendelian heredity. 



Tangibly illustrated, the result is that when, 

 for instance, a pea having a tall vine is crossed 

 with one having a short vine, the offspring will be 

 tall; but their offspring will be represented, on 

 the average, by one tall vine (pure dominant) 

 that will breed absolutely true, one short vine 



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