Biology · Grades 10–12
Variation beyond simple dominance · Revision sheet
Recognize incomplete dominance, codominance and polygenic traits.
Learn the idea
Incomplete dominance
A heterozygote can show an intermediate phenotype in a specified model.
Codominance
Both allele-associated products can be expressed in a heterozygote.
Polygenic
Many traits depend on multiple genes and often environmental conditions.
Evidence
A distribution of observed values does not alone identify the exact inheritance mechanism.
Explain without looking
- Why does a smooth bell-shaped distribution not prove a particular number of genes?
- Which question is scientifically stronger?
Further reading and review references
- openstax.org · reference 1
- www.genome.gov · reference 2
- www.genome.gov · reference 3
- www.genome.gov · reference 4
- www.genome.gov · reference 5
- www.genome.gov · reference 6
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Independent educational review required. Grade bands are approximate; these are not officially aligned curricula.