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Updated: June 7, 2025
I have endeavoured to find a case which would not be open to the above criticism that is, to find a character which could be considered somatogenic and which was absent in a closely allied variety. Most of the characters in domesticated varieties are obviously gametogenic mutations, but the lop-ear in rabbits may be, partly at least, somatogenic.
When the same male was mated with a normal black female the offspring were black with red hairs interspersed. All these experiments are open to the following criticism. It has been the main argument of this volume that there are two distinct kinds of characters in all organisms namely, those of somatogenic origin and those of gametogenic origin.
The majority of evolutionists in recent years have taught that influences exerted through the soma have no effect on the determinants in the chromosomes of the gametes, that all hereditary variations are gametogenic and none somatogenic.
At the same time there are some somatic sex-characters, e.g. in insects and birds, which do not appear to be correlated with changes in the gonads, and which are probably gametogenic, not somatogenic in origin. The theory of the heredity of somatogenic modifications is not in opposition to the mutation theory.
There is a very strong congenital or hereditary tendency to the disappearance of pigment from the lower side, and this is only overcome after long exposure to the light. On the other hand, if the disappearance of the pigment were due to a mutation, were gametogenic and entirely independent of external conditions, there would be no development of pigment after the longest exposure.
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