Partial repulsion { 1 (n-1) (n-1) 1 2n 4n^{ 2} from zygote { 1 31 31 1 64 4096 of form { 1 15 15 1 32 1024 Ab×aB { 1 7 7 1 16 256 { 1 3 3 1 8 64 1 1 1 1 4 16 Partial coupling { 3 1 1 3 8 64 from zygote { 7 1 1 7 16 256 of form { 15 1 1 15 32 1024 AB×ab { 31 1 1 31 64 4096 { 63 1 1 63 128 16384 { (n-1) 1 1 (n-1) 2n 4n^{ 2}
Nature of zygotic series --------------------------------------- AB Ab aB ab Partial repulsion { 2n^{ 2}+1 n^{ 2}-1 n^{ 2}-1 1 from zygote { 2049 1023 1023 1 of form { 513 255 255 1 Ab×aB { 129 63 63 1 { 33 15 15 1 9 3 3 1 { 41 7 7 9 Partial coupling { 177 15 15 49 from zygote { 737 31 31 225 of form { 3009 63 63 961 AB×ab { 12161 127 127 3969 { 3n^{ 2}-(2n - 1) 2n-1 2n-1 n^{ 2}-(2n-1)
the _parental combinations_ are in excess. This excess almost certainly follows the system indicated by the accompanying table. In the general expressions _n_ is half the number of gametes required to express the whole system. Now if we imagine that sex-factors are involved with the others concerned in such a relationship as this we have a system of distribution approximating to that found in _biennis_ and _muricata_. The difference in reciprocals is represented in a not improbable way. It cannot yet be said that the rarer terms in the series are formed at all, and perhaps they are not. As we pointed out in our discussion of these phenomena, the peculiar distribution of factors in these cases must be taken to mean that the planes of division at some critical stage in the segregation are determined with reference to the parental groups of factors, or in other words, that the whole system has a polarity, and that the distribution of factors with reference to this polarity differs according to the grouping of factors in the gametes which united in fertilization to produce the plant. Subsequent proliferation of cells representing certain combinations would then lead to excess of the gametes bearing them. It is on similar lines that I anticipate we shall hereafter find the interpretation of the curious facts discovered by de Vries, though it is evident that a long course of experiment and analysis must be carried through before any certainty is reached. The work must be begun by a careful study of the descent of some single factor, for example, that causing the broader leaf of _biennis_, and we may hope that the study of _Oenothera_ by proper analytical methods will no longer be deferred.