United States or Portugal ? Vote for the TOP Country of the Week !
In Mendelian experiments, a heterozygote individual is one arising from gametes containing opposite members of a pair of characters, in other words, from the union of a gamete carrying a dominant with another carrying a recessive. A pure recessive individual is one arising from the union of two gametes both carrying recessives.
It varied in different individuals, but in some, at any rate, was greater in later generations than in the earlier. The condition bred true, as pure recessives do; and when such an impure recessive was mated with a heterozygote with black skin, the offspring were half pigmented and half recessive, with some pigment on the abdomen of the latter.
Mephisto 4- 100% Mephisto | / | / | 77.5 % Dom. | / \ > All Mephisto \ | \ 9- all hybrids with 83-68% | 22.5 % Rec. dominants and 17-32% | recessives. 100% Danebrog. Danebrog Examining these figures we find one-fourth of constant recessives, as has already been said, further one-fourth of constant dominants, and the rest or one half as unstable hybrids.
These two were mated with coloured hens, and in later generations all the recessives instead of being pure white, like the Silky, had reddish-brown pigment distributed as in pile fowls. The back and tail were white. These pile-coloured fowls when mated together bred true, with individual differences in the offspring.
The dark hearted or dominants behaved in two different ways. Some of them remained true to their type, all their offspring being dark-hearted. Evidently they had returned to the parent with the active mark, and had reassumed this type as purely as the recessives had reached theirs.
For my crosses I have taken the dark-centered "Mephisto" and the "Danebrog," or Danish flag, with a white cross on a red field. The second year the hybrids were all true to the type of "Mephisto." Once more the flowers were self-pollinated and the visits of insects excluded. The recessives now gave only recessives, and hence we may conclude that the varietal marks had returned to stability.
So brown or black eyes, dark hair, curly hair, dark skin, and so on, are dominant, while blue or grey eyes, light or straight hair, light skin are recessives. A nervous temperament is dominant to the phlegmatic. A number of psychic qualities have been declared to be Mendelian unit factors: memory, mechanical instinct, mathematical ability, literary ability, musical ability, and even handwriting.
or heterozygote dominants and pure recessives in equal numbers. It is evident that the reproduction of the sexes is very similar to this. One of the remarkable facts about sex is that, although the uniting gametes are male and female yet they give rise to males and females in equal numbers. If one sex were a dominant this would be in accordance with Mendelian theory.
Briefly, the law states that when two pure traits or characters are crossed, one dominates in the first generation of offspring the other remaining hidden or recessive. Of the second generation, one-half the individuals are still mixed, bearing the dominant characteristic externally and the other hidden; one-fourth are pure dominants and one-fourth are pure recessives.
Both the pigmented skin of the Silky and the colour in the plumage of the bankiva are dominant, so that all the offspring in F1 or the first generation are coloured fowls with pigmented skins. But in later generations I found that with regard to skin pigment there were no pure recessives.