The choice of nucleotide changes in DNA evolution can be either selectively neutral or biased.
DNA分子进化中，对核苷酸替换的选择可呈选择中性或选择倾向性。
This situation is one commonly encountered by evolutionary biologists, who must often decide whether a characteristic is adaptive or selectively neutral.
这一情形乃进化论生物学家所经常遇见的现象，他们常常必须确定某一特征是否是适应性的，或在选择方面仅是中性的。
As part of plasma introduction to the deflection region a novel cryogenic pumping apparatus selectively removes neutral atoms from a plasma stream.
作为向偏转区域的等离子体引入的一部分，新颖的低温抽运设备选择性地从等离子体流中去除中性原子。
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