Another point, closely connected with Darwin's theory, on which the fossil history of plants has been supposed to have some bearing, is the question of Mutation, as opposed to indefinite variation. Arber and Parkin, in their interesting memoir on the Origin of Angiosperms, have suggested calling in Mutation to explain the apparently sudden transition from the cycadean to the angiospermous type of foliage, in late Mesozoic times, though they express themselves with much caution, and point out "a distinct danger that Mutation may become the last resort of the phylogenetically destitute"!英文原著 · 《Darwin and Modern Science》
'As often as a father kisseth his child, he should say secretly with himself' (said Epictetus,) 'tomorrow perchance shall he die.' But these words be ominous. No words ominous (said he) that signify anything that is natural: in very truth and deed not more ominous than this, 'to cut down grapes when they are ripe.' Green grapes, ripe grapes, dried grapes, or raisins: so many changes and mutations of one thing, not into that which was not absolutely, but rather so many several changes and mutations, not into that which hath no being at all, but into that which is not yet in being.英文原著 · 《The Meditations》
This gives a severe shock to the "Mutation theory," for the other ACTUALLY WILD species with which de Vries experimented showed no "mutations" but yielded only negative results.英文原著 · 《Darwin and Modern Science》
Of late, the study of variability has returned to the recognition of this distinction. Darwin's variations, which from time to time happen to arise, are MUTATIONS, the opposite type being commonly designed fluctuations. A large mass of facts, collected during the last few decades, has confirmed this view, which in Darwin's time could only be expressed with much reserve, and everyone knows that Darwin was always very careful in statements of this kind.英文原著 · 《Darwin and Modern Science》
Dwarf types are one of the commonest and most favourite varieties of flowering plants; they are not originated by a repeated selection of the smallest specimens, but appear at once, without intermediates and without any previous indication. In many instances they are only about half the height of the original type, thus constituting obvious novelties. So it is in other cases described by Korschinsky: these sports or mutations are now recognised to be the main source of varieties of horticultural plants.英文原著 · 《Darwin and Modern Science》
In contrast to these changes of the internal causes, the ordinary variability which is exhibited during the life-time of a species is called fluctuating variability. The name mutations or mutating variability is then given to the changes in the specific characters. It is desirable to consider these two main divisions of variability separately.英文原著 · 《Darwin and Modern Science》
I went to find out if I inherited a genetic mutation from my mom that means I'm probably gonna die of breast cancer.美剧 · 《Shameless》
I went to get a test done, to find out if I inherited a genetic mutation from my mom that means I'm probably gonna die of breast cancer.美剧 · 《Shameless》
You see, I'm a superior genetic mutation, uh, An improvement on the existing mediocre stock.美剧 · 《The Big Bang Theory》
That's not exactly a mutation that would get you Into Xavier's School for Gifted Youngsters, But go on.美剧 · 《The Big Bang Theory》