Hybrid inviability is a post-zygotic barrier, which reduces a hybrid's capacity to mature into a healthy, fit adult. The relatively low health of these hybrids relative to pure-breed individuals prevents gene flow between species.

What is an example of hybrid inviability?

Hybrid inviability

The hybrid embryos of sheep and goats, for example, die in the early developmental stages before birth. Hybrid inviability is common in plants, whose hybrid seeds often fail to germinate or die shortly after germination.

What is the difference between hybrid inviability and hybrid breakdown?

Hybrid Breakdown: This is similar to hybrid inviability or sterility, but skipping a generation. We get successful mating with viable, fertile offspring, but when the offspring try to have offspring, things go wrong. The second generation can be either inviable, infertile, or show reduced fitness.