LUTHER BURBANK 



his stoneless plums, white blackberries, and nu- 

 merous other new plant developments. 



MENDELIAN HEREDITY 



The discovery that second-generation hybrids 

 tend thus to recombine the characteristics of their 

 grandparents in new combinations has been made 

 even earlier by an experimenter whose work for 

 the time being was ignored, but who subsequently 

 came to posthumous fame through the rediscovery 

 of his work about the beginning of the present 

 century. This was the Austro-Silesian monk, 

 Mendel. He had not only made independently 

 the discovery that had meant so much in Mr. Bur- 

 bank's work, but he had followed it out with 

 numerical computations that gave him a very 

 definite notion as to the exact way in which the 

 divergent traits of any given pair of parents 

 would be combined in their descendants. 



Mendel's work was chiefly done with the gar- 

 den pea, and he dealt with qualities that are 

 mutually exclusive large size versus small size, 

 for example, in the case of the pea, or yellow pods 

 versus green pods, or pink flowers versus white 

 flowers. 



To state the simplest case, Mendel found that 

 when a tall race of peas is crossed with a short 

 race the progeny are all tall; but the quality of 

 shortness, although for the moment suppressed, is 

 not lost, but reappears in about one in four of 

 the progeny of the next generation. 



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