GED Science TestLife ScienceEasy
A gardener notices that a specific type of plant consistently produces either red flowers or white flowers, but never pink flowers, even when crossing red and white parents. Which of the following inheritance patterns does this observation most accurately represent?
- AComplete dominance
- BPolygenic inheritance
- CCodominance
- DIncomplete dominance
Show answer & explanationAnswer & explanation
Correct answer: A. Complete dominance
In complete dominance, one allele completely masks the expression of the other, resulting in only two distinct phenotypes even in heterozygotes.
Why the other options are wrong
- B. Polygenic inheritance involves multiple genes contributing to a trait, often resulting in a continuous range of phenotypes, not distinct categories like this.
- C. Codominance would result in both red and white patches or a mixture, where both alleles are expressed, not a single blended color.
- D. Incomplete dominance would result in an intermediate phenotype, such as pink flowers, which is not observed here.
Complete Dominance
An inheritance pattern where one allele completely masks the expression of the other allele in the heterozygous state.
- Only two distinct phenotypes are observed for a given trait.
- Heterozygotes express the dominant phenotype.
- Example: Mendel's pea plants (tall/short, purple/white flowers).
Memory trick: Dominance is like a king, completely ruling over its subject.