codominance
LowTechnical/Scientific
Definition
Meaning
A genetic relationship where two different alleles for a trait are both fully expressed in the phenotype of a heterozygous individual, resulting in a blended or mixed appearance rather than one trait dominating the other.
In broader contexts, can refer to any situation where two distinct elements, forces, or principles coexist with equal prominence and influence, without one subordinating the other.
Linguistics
Semantic Notes
Primarily a term of genetics and biology. The concept is specific and not used metaphorically in general language, though the 'co-' prefix implies shared, equal expression.
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or usage. Spelling and pronunciation are consistent.
Connotations
Purely technical, neutral connotation in both varieties.
Frequency
Equally low-frequency in both UK and US English, confined to biological sciences.
Vocabulary
Collocations
Grammar
Valency Patterns
[Subject] exhibits codominance.Codominance occurs in [organism/trait].This is a case of codominance.Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Usage
Context Usage
Business
Not used.
Academic
Used in genetics textbooks and research papers to describe specific inheritance patterns.
Everyday
Virtually never used.
Technical
Core term in genetics, molecular biology, and related life sciences.
Examples
By Part of Speech
verb
British English
- The alleles for blood type A and B codominate in the AB phenotype.
- These two genes can codominate under certain conditions.
American English
- The alleles for blood type A and B codominate in the AB phenotype.
- In this cross, the traits codominate.
adverb
British English
- The traits were expressed codominantly.
- The genes act codominantly in the heterozygote.
American English
- The traits were expressed codominantly.
- The alleles function codominantly.
adjective
British English
- The codominant alleles were both visible in the flower's petals.
- This is a codominant inheritance pattern.
American English
- The codominant alleles were both visible in the flower's petals.
- ABO blood groups are a codominant system.
Examples
By CEFR Level
- In some flowers, red and white colours can appear together because of codominance.
- Codominance is different from one trait hiding another.
- The ABO blood group system in humans is a classic example of codominance, where the A and B alleles are both expressed in type AB blood.
- Researchers observed codominance in the plumage patterns, with both parental colour patches distinctly visible.
- The molecular basis of codominance often lies in the fact that both alleles produce functional proteins that contribute independently to the phenotype.
- Unlike incomplete dominance, which yields an intermediate phenotype, codominance results in the simultaneous expression of both parental traits without blending.
Learning
Memory Aids
Mnemonic
Think of CO-DRIVERS: both are driving (dominating) the car equally, just as both alleles are expressed equally in codominance.
Conceptual Metaphor
GENETIC EXPRESSION IS A SHARED RESPONSIBILITY / TWO VOICES SPEAKING AT EQUAL VOLUME.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid translating as 'содоминирование' (incorrect). The correct biological term is 'кодоминирование'.
- Do not confuse with 'неполное доминирование' (incomplete dominance), which produces an intermediate blend, whereas codominance shows both traits distinctly.
Common Mistakes
- Confusing codominance with incomplete dominance (blending).
- Using 'codominance' to describe social or political power-sharing (incorrect extension).
- Misspelling as 'co-dominance' (hyphen is generally not used in modern scientific writing).
Practice
Quiz
Which of the following best describes codominance?
FAQ
Frequently Asked Questions
In codominance, both alleles are fully and separately expressed (e.g., red and white spots). In incomplete dominance, the heterozygous phenotype is a blended intermediate of the two (e.g., pink flowers from red and white parents).
It is less common than complete dominance but is a standard inheritance pattern for specific traits, such as human ABO blood types and certain coat colours in animals.
Yes, but the Punnett square will show genotypes, and you must know that the heterozygous genotype results in a phenotype expressing both alleles, not a blend or a dominant one.
No, it is an extension of them. Mendel's principle of segregation still holds (alleles separate during gamete formation), but the principle of dominance does not apply, as neither allele is recessive.