Which concept describes a pattern where hybrids are viable and fertile, but their offspring are weak or sterile?

Which concept describes a pattern where hybrids are viable and fertile, but their offspring are weak or sterile?

• A. Phylogeny
• B. Reduced Hybrid Viability
• C. Hybrid Breakdown
• D. Reduced Hybrid Fertility

Answer: (C)

Hybrids that are viable and fertile, but their offspring are weak or sterile illustrate hybrid breakdown. This pattern is a postzygotic isolating mechanism: the first-generation hybrids can survive and reproduce, but when they mate with each other or backcross to the parent species, the next generation shows reduced viability or infertility. The problems arise from genetic incompatibilities that don’t appear in the F1 but show up in F2 or later generations as new allele combinations come together. This helps keep species separate because gene flow is limited by the poor performance of the hybrids’ offspring.

Hybrids that are viable and fertile, but their offspring are weak or sterile illustrate hybrid breakdown. This pattern is a postzygotic isolating mechanism: the first-generation hybrids can survive and reproduce, but when they mate with each other or backcross to the parent species, the next generation shows reduced viability or infertility. The problems arise from genetic incompatibilities that don’t appear in the F1 but show up in F2 or later generations as new allele combinations come together. This helps keep species separate because gene flow is limited by the poor performance of the hybrids’ offspring.