On Gametic Series involving Reduplication of 
certain Terms. 
This paper appears with slight modifications in Jour. Genetics 1911. 
by W. Bateson & R. C. Punnett. 
In a paper recently published ^) we gave a brief account 
of some peculiar phenomena relating to the coupling and repulsion 
of factors in the gametogene sis of the sweet pea and of several 
other plants. The view there stated was that if A and B represent 
two factors between which coupHng 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 according to a definite 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 band 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 
account to which we have alluded we supposed that such repulsion 
was complete^ 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 conception 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 
account 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 account 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, 
1) Proc. Roy. Soc. B, vol. 84, 1911, p. 1. 
