. Animal biology. Zoology; Biology. INHERITANCE IN ORGANISMS 563 one white recessive. Another case of incomplete dominance is that of the blue Andalusian fowl (Fig. 387), which is a hybrid between a black individual and an individual which is white splashed with black. When two blue Andalusians are bred, there is a ratio of one splashed white, one black, and two blue individuals. Another variation is that due to the cumulative effect of multiple genes. This is observed in mulattoes, whose skin color may vary from very dark to very light. It also has been found that there are lethal P Gen. F2 G
. Animal biology. Zoology; Biology. INHERITANCE IN ORGANISMS 563 one white recessive. Another case of incomplete dominance is that of the blue Andalusian fowl (Fig. 387), which is a hybrid between a black individual and an individual which is white splashed with black. When two blue Andalusians are bred, there is a ratio of one splashed white, one black, and two blue individuals. Another variation is that due to the cumulative effect of multiple genes. This is observed in mulattoes, whose skin color may vary from very dark to very light. It also has been found that there are lethal P Gen. F2 Gen. Fig. 387.—Incomplete dominance, as illustrated by the blue Andalusian fowl. The P generation is splashed white and black, the Fi generation all blue, and the F2 generation, one splashed white, two blue, and one black. genes, which when present in pairs cause the death of the organism. In some cases, as walnut combs in fowl, the character is believed to result from the interaction of two genes, either kind of which, when in a homo- zygous pair, produces a different comb pattern. 606. Breeding for Certain Characteristics.—In both animal and plant breeding the end sought is the bringing together of desirable characters and the development of stock which will breed true for those characters. This involves the careful selection of breeding animals and the elimina- tion of all progeny which are not homozygous for each pair of characters desired. In this way, and by persistent inbreeding, a line can gradually be developed which not only possesses the desired characters but also. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Wolcott, Robert Henry, 1868-1934; University of Nebraska (Lincoln campus). Dept. of Zoology. New York ; London : McGraw-Hill Book Company, Inc.
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