换句话说，鼹钝口螈的变态是一种返祖现象。

In other words, metamorphosis in mole salamanders is an atavism.

youdao

如果多洛定律是正确的，返祖现象应该很少发生。

If Dollo's law is right, atavisms should occur only very rarely.

youdao

如果因为任何原因，这些事情没有发生，祖先的种种特性也许就不会消失，从而导致返祖现象。

If for any reason this does not happen, the ancestral feature may not disappear, leading to an atavism.

youdao