Which concept describes the breakdown of hybrid fitness across generations?

Which concept describes the breakdown of hybrid fitness across generations?

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

Answer: (C)

Hybrid breakdown is about how hybrid fitness can decline in later generations due to genetic incompatibilities that only appear after recombination or segregation in offspring. First-generation hybrids between two species may be viable and fertile because each parent contributes a compatible set of alleles, but when those hybrids mate or backcross to a parent, new allele combinations can interact poorly. This leads to reduced viability or fertility in the next generations, a pattern known as hybrid breakdown. This concept reflects how incompatibilities accumulate in separate lineages and only become problematic when mixed in subsequent generations. The other terms describe different ideas: phylogeny is about evolutionary relationships, reduced hybrid fertility refers to hybrid sterility, and reduced hybrid viability refers to lower survival of hybrids—none specifically capture the generational decline described by hybrid breakdown.

Hybrid breakdown is about how hybrid fitness can decline in later generations due to genetic incompatibilities that only appear after recombination or segregation in offspring. First-generation hybrids between two species may be viable and fertile because each parent contributes a compatible set of alleles, but when those hybrids mate or backcross to a parent, new allele combinations can interact poorly. This leads to reduced viability or fertility in the next generations, a pattern known as hybrid breakdown. This concept reflects how incompatibilities accumulate in separate lineages and only become problematic when mixed in subsequent generations. The other terms describe different ideas: phylogeny is about evolutionary relationships, reduced hybrid fertility refers to hybrid sterility, and reduced hybrid viability refers to lower survival of hybrids—none specifically capture the generational decline described by hybrid breakdown.