杂种繁殖

Individuals crossing exclusively within the same population produce more progeny than those crossing in both directions and thereby use up some of their gametes for the production of inviable hybrids.

完全在同一种行杂交的个体比以两个方向行杂交的个体繁殖后代要多，因此为了产无机的杂种，就要消耗掉一些配子。