Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: May 19, 2025
The addresses, however, were not solely concerned with throwing contempt upon views which were yesterday of great respectability, and which even to-day are as gospel to many. They devoted themselves chiefly to the consideration of the question of heredity, viewed, as might be expected, from the Mendelian standpoint.
He has not only studied the chromosomes in the gametes of this fly, and made Mendelian crosses with it, but has obtained numerous mutations, so that his work is a very important contribution to the mutation doctrine. Drosophila in the hands of Professor Morgan and his students and colleagues has thus become as classical a type as Oenothera in those of the botanical mutationists.
This, of course, is contrary to the results of ordinary Mendelian experiments, for characters are inherited equally from individuals of either sex, except secondary sexual characters and sex-linked characters which we shall consider later.
Intersexes in moths; Bird intersexes; Higher metabolism of males; Quantitative difference between sex factors; Old ideas of intersexuality; Modern surgery and human intersexes; Quantitative theory a Mendelian explanation; Peculiar complication in the case of man; Chemical life cycles of the sexes; Functional-reproductive period and the sex problem; Relative significance of physiological sex differences.
We are interested rather in those more specific traits or characters, mental or physical, which, in the Mendelian view, are structural and functional units, making up a mosaic rather than a blend. The laws of heredity are concerned with the precise behavior, during a series of generations, of these specific unit characters.
Just as the old embryologists conceived the adult individual to be contained with all its organs to the most minute details within the protoplasm of the fertilised ovum or one of the gametes, so the modern Mendelian, because he is unable to conceive or to obtain the evidence of the gradual development of a hereditary factor, conceives all the hereditary factors of the whole animal kingdom packed in infinite complexity within the protoplasm of the primordial living cells.
In other terms, if a hybrid of the first generation is not allowed to fertilize itself, but is pollinated by one of its parents, the result will be in accordance with the Mendelian formula. In order to see an effect on the spikes produced in this way, it is of course necessary to fertilize them with the pollen of the variety, and not with that of the specific type.
One will have two H's, or the double factor for horns, and hence will exhibit horns as will also the two HA's since a single dose of horns expresses them in a male. So we have the three-to-one Mendelian ratio. The AA, lacking the factor entirely, cannot have horns. Nor will the two HA females have horns, a single dose being insufficient to express them in a female.
Ancient biographers, little concerned with Mendelian speculation, have not reported from what stock his family sprang. Scientific curiosity and nationalistic egotism have compelled modern biographers to become anthropologists.
We naturally ask, then, how the two parents are concerned in this matter; and the first remarkable answer returned by the Mendelian workers during the last three or four years is that it is the mother who determines the sex of her children in the case of all the higher animals.
Word Of The Day
Others Looking