On Gametic Series involving Reduplication of 

 certain Terms. 



This paper appears with slight modifications in Jour. Gene ti es 1911. 

 by W. Bateson & R. C. Punnett. 



In a paper recently published *) we gave a brief aecount 

 of some peculiar phenoinena relating to the coupling and repulsion 

 of factors in the gametogenesis of the sweet pea and of several 

 other plants. The view there stated was that if A and B represent 

 two factors between which coupling or repulsion can exist then 

 the nature of the F2 generation depends upon whether A and B were 

 carried into the Fi heterozygote by the same gamete or by 

 different gametes. If the heterozygote AaBb is formed by the 

 gametes AB and ab partial coupling between A and B occurs in 

 F2 aecording to a delinite System, and it must be supposed that 

 the gametes formed by the heterozygote belong to one or other 

 of the series 



3 AB : Ab : aB : 3 ab 

 7 AB : Ab : aB : 7 ab 



15 AB : Ab : aB : 15 ab, &c. 



If on the other hand the heterozygote AaBb is formed by 

 the gametes Ab and aB repulsion occurs between A and B, so that 

 only the two classes of gametes Ab and aB are formed. In the 

 aecount to which we have alluded we supposed that such repulsion 

 was eomplete, and that the two classes of gamete AB and ab 

 were not formed. Our work on sweet peas during the present 

 summer has led us to modify our coneeption of the nature of the 

 gametes produced in cases where repulsion occurs, and this modi- 

 fication will perhaps be made clearer if we begin by giving an 

 aecount of the experiments upon which it is based. 



During the years 1906 and 1907 we were engaged upon 

 an investigation of the inheritance of the hooded character in the 

 sweet pea of which an aecount appeared in Report IV to the 

 Evolution Committee of the Royal Society, 1908, pp. 7—15. Among 

 several thousand plants bred and recorded in this set of experi- 

 ments there occurred a single individual (in Exp. 35, R. E. C. IV, 



i) Proc. Roy. Soc. B, vol. 84, 1911, p. 1. 



