And this is what happens with small populations and inbreeding of close relatives.

当一个物种的种群数量稀少而又不得不近亲繁殖时，灭绝就会发生。

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Darwin realized the dangers of inbreeding and wondered if his close genetic relation to his wife had had an ill impact on his children's health, three (of 10) of whom died before the age of 11.

达尔文意识到近亲结婚的危险，并且怀疑过自己和妻子相近的基因关系是不是对他们的孩子的健康造成了不良影响，他们的(10个中的)三个孩子在11岁之前就死去了。

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