BRAINCAKECodominance
Codominance occurs when two different alleles of a gene are both expressed in the phenotype of a heterozygote. Neither allele is recessive, so the heterozygote shows the characteristics of both alleles, rather than a blend.
Because neither allele is dominant, capital and lower-case letters are not used. Instead, the gene is shown by a capital letter with the alleles written as superscripts, for example CR and CW.
Example 1: coat colour in shorthorn cattle. The allele CR codes for red hair and CW for white hair.
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More in Genetics and Variation
- Species
- Allopatric Speciation
- Sympatric Speciation
- Artificial Selection
- Codominance Genetic Crosses
- Multiple Alleles
- Multiple Allele Crosses - ABO Blood Groups
- Autosomal Linkage and Recombinant Offspring
All 41 lessons in Genetics and Variation · All OCR A-level Biology topics