Neo-Mendelism 73 



Another factor that may obscure these results is what 

 is called physical correlation. For example, a corn 

 plant of small size but with the hereditary capacity for 

 producing large ears could not fully express this capacity. 

 It could not produce as large ears as if it had been a 

 large-sized plant. 



Still another factor that might obscure the result 

 may be called gametic correlation, which is a conception 

 presented by East. The idea is that factors which are 

 inherited quite independently and which affect different 

 plant characters might still be conceived of as having an 

 influence upon one another. As East puts it, "A gamete 

 may be a mosaic of independent factors, but the plant 

 (produced from the gametes) will not be a mosaic of all 

 the characters and factors produced, for these factors 

 act and react upon one another in complex ways during 

 their development." 



Such are some of the conditions or factors that tend 

 to obscure results in the F2 generation and give rise to 

 ratios hard to interpret. The weaker the influence of 

 these factors the more clearly do the phenomena of 

 cumulative factors come out. The total result of this 

 phase of East's work, in spite of obscuring conditions 

 that have arisen, has been to strengthen greatly the 

 conception of cumulative factors. A summary of his 

 conclusions may be stated as follows: 



When one is dealing with quantitative characters, that is, 

 those produced by cumulative factors, he is confronted by exactly 

 the same principles of Mendel ian inheritance as have long been 

 known to apply to qualitative characters. With quantitative 

 characters, however, the problem is more complex, due chiefly to 

 two things: (i) we are usually dealing with more factors, and 



