66 Study of Right- arid Left-Haiidedness 



An alternative explanation would be possible on the basis of a 

 hypothesis of a somatic segregation of characters^ if it be assumed 

 (i) that the characters of right- and left-handedness are represented in 

 the gametes, and (ii) that odd rows tend to produce an excess of female 

 gametes bearing right-handedness, even rows an excess of those bearing 

 the character for left-handedness. (The male gametes may be left out 

 of account when considering large numbers, for pollination is anemo- 

 philous and promiscuous.) 



The alternative explanations are (i) that the influence determining 

 the fold of the first leaf is of a feeble nature and acts upon the gamete 

 or embryo, which itself has no special inclination to become right- or 

 left-handed, but must choose one or the other : or (ii) that the female 

 gametes are definitely right- or left-handed, and that a certain amount 

 of somatic segregation occurs. 



In order to maintain this latter alternative explanation it would be 

 necessary to show that right- and left-handedness in Maize are in some 

 way hereditary characters. The statistics give strong evidence that 

 this is not the case. Almost all the 17 Maize cobs studied gave 

 ratios between lefts and rights very nearly alike (p. 62) : but it is 

 almost inconceivable that in every case the parent plant should have 

 had the same direction of fold in its first leaf. 



It is evident that in different cereals there are tendencies to produce 

 different ratios ; Barley for instance gave a very different result from 

 Oats : and it is possible that the inverse ratios given by Maize cob XI 

 point to some similar divergencies between different varieties of Maize. 

 But the fact that different plants give different ratios and that (in the 

 case of Barley at least) the ratio is constant for successive generations 

 does not imply that the characters of right- and left-handedness them- 

 selves are hereditary. 



We may therefore conclude that there is no evidence for the 

 inheritance of the direction of fold in the first leaf of Maize : and this 

 conclusion harmonises with the similar one previously reached in the 

 case of Barley. A further argument against the second alternative 

 explanation is the fact that, though much sought, up to the present no 

 direct proof of somatic segregation affecting gametes of the same sex 

 has been obtained, however probable the existence of such a phenomenon 

 may appear. 



1 See W. Bateson and E. C. Punnett, "On the Inter-relations of Genetic Factors." 

 Proc. Roy. Soc. B, Vol. lxxxiv. p. 6, 1911. " On Gametic Series involving Reduplication of 

 certain Terms," Verh. d. naturf. Ver. inBrilnn, Bd. xlix. 1911 and Journ. Genet. Vol. 1. 1911. 



