Most parents are heterozygotes with one normal allele and one mutated allele.

大多数父母是一个正常等位基因和一个突变等位基因的杂合子。

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Because the normal allele (a) can completely cancel the mutant allele (a), animals with Aa or Aa look the same.

因为正常等位基因(A)可以完全取消突变等位基因(一)，动物使用AA或AA看起来是一样的。

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Haploinsufficiency --- A cause of genetic disease in which the contribution from a normal allele is insufficient to prevent disease because of a loss-of-function mutation at the other allele.

遗传病的原因之一，单倍的基因剂量不足以维持正常功能。

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