314 Forms of Rechiplication 



and if so, of what typo must it be? We need only state now tliat the 

 answer is that there is reduph'cation between B and C of the type 



nm +1 : « + m : n + m : rim + 1. 

 The mode by which this ratio is found is given below. We have 

 however to note that this type of ratio also does not conform to the 

 Bateson-Punnett formula. 



Certain experimental results will, I believe, in view of these con- 

 clusions, repay further study. All the gold has not yet been extracted 

 from the ore. 



Reduplication clearly depends upon peculiarities in the mode of 

 formation of the gametic series. As however it, so far as we know 

 at present, affects pairs of factors only, it is convenient to ignore such 

 possible cases of reduplication as might occur between, say, triplets or 

 quartets. With this limitation and adopting the Bateson-Punnett 

 hypothesis of reduplication {Jouni. of Genetics, Vol. I. No. 4, p. 293), 

 it is quite easy to construct the gametic series for any set of re- 

 duplications. 



Let us consider first the simple case in which three factors A, B and 

 C are involved, with reduplication between A and B only, and in the 

 form n : 1 : 1 : n. 



The gametic series if A and B are alone considered would be 

 ?iAB + lAb + laB + nab. 

 To include the factor C, the series must consist of eight terms and be 

 arranged so that each member of the above will be associated with C 

 and c, without disturbing the established redui)lication ; thus 



9iABC -1- «ABc -f- lAbC -I- lAbc -I- laBC + laBc -I- ?iabC + «abc. 

 By extracting the pairs separately from this series, we get 



AB : Ab : aB : ab :: 2)i : 2 2 : 2?( or ii : \ : \ : n. 



AC : Ac : aC : ac :: /i -I- 1 : /( + 1 : rt -I- 1 : M -f- 1 or 1:1:1:1. 



BC : Be : bC : be :: ;i + I : /I + 1 : /I -t- 1 : « -1- 1 or 1:1:1:1. 

 Clearly a reduplication between two factors A and B does not alter the 

 ratios for A and C and B and C. 



An experimental illustration of this is furnished by Gregory's work 

 on Primula sinensis, in what may be called the MSD group of experi- 

 ments ; where 



M = magenta dominant over m = red ; 

 and S = short style „ „ s = long style ; 



and D = single flower „ „ d = double flower. 



