Genetics in Relation to Agriculture

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McGraw-Hill, 1918 - Animal breeding - 675 pages
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Page 482 - In every animal which has not passed the limit of its development, a more frequent and continuous use of any organ gradually strengthens, develops and enlarges that organ, and gives it a power proportional to the length of time it has been so used; while the permanent disuse of any organ imperceptibly weakens and deteriorates it, and progressively diminishes its functional capacity, until it finally disappears.
Page 565 - Their colour is bay, marked more or less like the quagga in a darker tint. Both are distinguished by the dark line along the ridge of the back, the dark stripes across the fore-hand, and the dark bars across the back part of the legs.
Page 78 - ... 6. To the difference in the position of the flowers. They are either axial, that is, distributed along the main stem; or they are terminal, that is, bunched at the top of the stem and arranged almost in a false umbel; in this case the upper part of the stem is more or less widened in section (P.
Page 54 - If r is more than six times the size of the probable error, the existence of correlation is a practical certainty.
Page 565 - That of the colt is long, but so stiff as to arch upward and to hang clear of the sides of the neck, in which circumstance it resembles that of the hybrid. This is the more remarkable, as the manes of the Arabian breed hang lank, and closer to the neck than those of most others.
Page 565 - They have the character of the Arabian breed as decidedly as can be expected, where fifteen-sixteenths of the blood are Arabian ; and they are fine specimens of that breed ; but both in their colour and in the hair of their manes, they have a striking resemblance to the quagga.
Page 565 - ... forehand of the colt are confined to the withers, and to the part of the neck next to them; those on the filly cover nearly the whole of the neck, and the back as far as the flanks. The colour of her coat on the neck adjoining to the mane is pale and approaching to dun, rendering the stripes there more conspicuous than those on the colt. The same pale tint appears in a less degree on the rump ; and in this circumstance of the dun tint also she resembles the quagga.
Page 565 - OUSELEY'S stud groom alleged that it never was otherwise. That of the colt is long, but so stiff as to arch upwards, and to hang clear of the sides of the neck ; in which circumstance it resembles that of the hybrid.
Page 326 - PELLEW (1910) have recently suggested that 'the greater height and vigor which the F\ generation of hybrids commonly exhibit may be due to the meeting in the zygote of dominant growth factors of more than one allelomorphic pair, one (or more) provided by the gametes of one parent, the other (or others) by the gametes of the other parent.
Page 481 - Shull defines acquired characters as ''those modifications of bodily structure or habit which are impressed upon the organism during its individual life." As Thompson has stated it, the precise question at issue is this: "Can a structural change in the body, induced by some change in use or disuse or by a change in surrounding influence, affect the germ cells in such a specific or representative way that the offspring will through its inheritance exhibit, even in a slight degree, the modifications...

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