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。
2
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.