MENDELISM 



97 



l t. MENDEL'S EXPERIMENTS ON GARDEN PEAS 



JVhat Mendel did was to hybridize certain varieties 

 garden peas and keep an exact record of all the 

 igeny, in itself a simple process but one that had 

 ;ver been faithfully carried out by any one. 

 "To Mendel's foresight in arranging the conditions 

 his work, as much as to his astuteness in interpreting 

 e data, is due his remarkable success." (Morgan.) 

 Before examining Mendel's results it may be well to 

 late the difference between normal and artificial self- 

 :ilization. Self-fertilization occurs when from the 

 >llen and ovule of the same flower are derived the two 

 imetes which uniting produce a zygote that develops 

 [to the seed and subsequently into the adult plant of 

 next generation. In artificially crossing normally 

 [f-fertilized flowers it is necessary to carefully re- 

 ive the stamens from one flower while its pollen is 

 ill immature, and later, at the proper time, to transfer 

 it ripe pollen from another flower. 

 [Mendel's cross-breeding experiments on peas showed 

 ;ain numerical relations among the progeny which 

 re rise to what has come to be rather indefinitely 

 as "Mendel's law." This law may be temporarily 

 ftrmulated as follows : 



B*Vhen parents that are unlike with respect to any 

 acter are crossed, the progeny of the first genera- 

 will apparently be like one of the parents with 

 to the character in question. The parent 

 nresses its character upon the offspring in this 

 manner is called the dominant. When, however, the 

 Jiybrid offspring of this first generation are in turn 



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