Page:Mendel's principles of heredity; a defence.pdf/49

 allelomorph, and we can speak of the integral characters which constitute it as hypallelomorphs. We ought to write the heterozygote (A A′ A′′) B and the gametes produced. by it may be of the form A, A′, A′′, A′′′,B. Or the resolution may be incomplete in various degrees, as we already suspect from certain instances; in which case we may have gametes A, A′A′′, A′′′ A′′′′, A′A′′ Av,B, and Each of these may meet a similar or a dissimilar gamete in fertilisation, forming either a homozygote, or a heterozygote with its distinct properties.

In the case of compound allelomorphs we know as yet nothing of the statistical relations of the several gametes.

Thus we have the conception

(5) of a Compound character, borne by one gamete, transmitted entire as a single character so long as fertilisation only occurs between like gametes, or is, in other words, "symmetrical," but if fertilisation take place with a dissimilar gamete (or possibly by other causes), resolved into integral constituent-characters, each separately transmissible.

Next, as, by the union of the gametes bearing the various hypallelomorphs with other such gametes, or with gametes bearing simple allelomorphs, in fertilisation, a number of new zygotes will be formed, such as may not have been seen before in the breed: these will inevitably be spoken of as varieties; and it is difficult not to extend the idea of variation to them. To distinguish these from other variations—which there must surely be—we may call them

(6) Analytical variations in contradistinction to

(7) Synthetical variations, occurring not by the separation of pre-existing constituent-characters but by the addition of new characters.