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Updated: May 20, 2025
His advisor was fortunately able to go the whole way with him as he discussed his hereditary "inevitables" the whole way and then, savingly, some steps beyond and for the first time Kent's understanding, now reaching for higher truths than would satisfy the fatalist, was wisely, personally conducted through a wholesome interpretation of the distinction between the heritage of germinal and of somatic attributes, that vital distinction: that it takes but two ancestors to determine the species of the offspring, but that the individual's personal heritage is the result of, and may be influenced by, a thousand forerunners; that dominant characteristics, compelling though they seem, may be neutralized by obscure, recessive characteristics.
"Then there were no recessive traits in her family," asked Kennedy quickly, "of the same sort that you find in the Athertons?" "None that we could discover," answered Dr. Crafts positively. "No epilepsy, no insanity of any form?" "No. Of course, you understand that almost no one is what might be called eugenically perfect.
The recessive character in this case is linked to the female sex chromosome, or, as Bateson described it, the dominant character is repelled by the sex-factor. We may make a diagram of the kind given by Morgan if we use a rod of different shape for the female-producing sex-chromosome, and use the black rod for the dominant character:
Or as it is equally often put, the one dominates and the other is recessive. In this terminology the character of the species is dominant in the hybrid while that of the variety is recessive. Hence it follows that in the hybrid the latent or dormant unit is recessive, but it does not follow that these three terms have the same meaning, as we shall see presently.
The term recessive only applies to the peculiar state into which the latent character has come in the hybrid by its pairing with the antagonistic active unit. In the first place it is of the highest importance to consider crosses between varieties of recorded origin and the species from which they have sprung.
In accordance with the view that the dominant is something present which is absent in the recessive, the Mendelian theory of sex assumes that femaleness is dominant, and that maleness is the absence of femaleness, the absence of something which makes the individual female.
When two such gametes unite in fertilisation the resulting organism will be a homozygous recessive, and the corresponding character will be absent. In this way we can conceive the origin of albino individuals from a coloured race, supposing the colour was due to a single factor. In Bateson's opinion the origin of a new dominant is a much more difficult problem.
A recessive character is the absence of some positive character, and if in the cell-divisions of gametogenesis the factor for the positive character passes wholly into one cell, the other will be without it, will not 'carry' that factor.
In any case the mere separation among different individuals of factors originally inherited together in one complex does not account for the origin of the complex or of the factors. This is somewhat the same idea as that of Bateson when he states that it is easy to understand the origin of a recessive character but difficult to conceive the origin of a dominant.
Bateson's explanation is that the female, according to the Mendelian theory of sex, is heterozygous in sex, the male homozygous and recessive, and that lacticolor is linked with the female sex-character, grossulariata being repelled by that character. Thus we have, the lacticolor character being recessive,
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