Due to biological incompatibilities, most species cannot reproduce with each other, save for a few exceptions such as interspecies rids like lions and tigers, or donkeys and horses. 在生物学上，大多数物种由于不相容性而不能相互繁衍后代，但也有例外，如狮子与老虎、驴与马等动物之间的杂交。
What hinders the process of interbreeding among species, and what is the maximum genetic divergence that still allows for successful reproduction? 是什么阻碍了物种之间的杂交过程？什么程度的基因差异仍能允许成功繁殖？
Analogizing the situations of interspecies reproduction to a metaphor of zippers, consider the case of a tiger mother and a donkey father, as if they were zippers. 通过拉链的比喻来类比不同物种之间的繁殖情况，想象一下老虎妈妈和驴爸爸的情况。
In the metaphor of zippers, the "teeth" of a tiger's zipper are akin to its robust nature, comparable to the strong teeth found in a snowsuit. 在拉链的比喻中，老虎的拉链“齿”就像其强壮的特性，类似于雪地服中坚固的拉链齿。
On the other hand, the "teeth" of a donkey's zipper are delicate, resembling the small yet precise ones found on delicate clothing. 相比之下，驴子的拉链“齿”则非常精致，类似于精致衣服上那些小巧而精确的拉链齿。
Trying to align the two different types of zippers would be like trying to match the incompatible traits of two different species; they sim do not fit together. 试图将这两种不同类型的拉链对齐，就如同试图匹配两种不同物种的不相容特征；它们根本无法匹配。
However, if two zippers were similar enough, such as those found on a horse and a donkey or a lion and a tiger, they might align metaphorically in terms of their biological compatibility. 如果两种拉链足够相似，比如马和驴或狮子与老虎身上的拉链，那么从生物学上的相容性来看，它们可能就会“匹配”。
Although not perfect, such alignments may suggest a certain level of compatibility that allows for interspecies ridization under certain conditions. 尽管并不完美，但这种“匹配”可能表明在某种程度上存在着一定程度的相容性，允许在某些条件下进行跨物种杂交。