What term describes offspring showing trait values beyond the range of both parents due to recombination?

• A. Overdominance.
• B. Hybrid breakdown.
• C. Disjunctive inheritance.
• D. Transgressive segregation.

Answer: (D)

This question is about how recombination can produce offspring with trait values that exceed the parental range. That phenomenon is called transgressive segregation.

Transgressive segregation occurs when the alleles that contribute to a trait come from both parents in new combinations, especially when multiple genes contribute additively. Some offspring inherit more of the high-effect alleles from both sides (or more of the low-effect alleles), pushing the trait values beyond what either parent exhibits. This leads to some hybrids being more extreme—either higher or lower—than both parents.

For example, if several genes influence plant height and each parent carries a mix of alleles, recombination can assemble a configuration that yields exceptionally tall or short offspring, even though the parents themselves aren’t extreme.

Overdominance refers to a heterozygote advantage, focusing on fitness rather than whether trait values exceed parental ranges. Hybrid breakdown involves reduced viability or fertility in later generations, not the appearance of extreme trait values. Disjunctive inheritance isn’t a standard concept explaining this pattern.