hybrid sterility

Hybrid sterility occurs when offspring resulting from the mating of two different species are unable to produce living young. This is a type of reproductive isolating mechanism that prevents gene flow between species. For example, mules, which are a hybrid of a horse and a donkey, are sterile.123

While some hybrids are sterile, others can be fertile and even lead to the formation of new species. Hybridization increases genetic diversity within a species, which is crucial for evolution and adaptation to changing environments. In plants, hybrid varieties can exhibit increased vigor and yield, a phenomenon known as heterosis, which is important in agriculture. However, in some cases, hybrid offspring may be poorly viable or sterile, a condition known as hybrid breakdown.143