gen-define-codominance-and-give-one-short-worked-example-b76d

Define codominance and give one short worked example.

# Codominance **Definition:** Codominance is a type of inheritance pattern where both alleles in a heterozygote are fully expressed simultaneously, with neither allele being dominant or recessive. Both traits appear together in the phenotype. ## Worked Example: ABO Blood Type (A and B alleles) **Cross:** A person with Type AB blood × A person with Type B blood **Genotypes:** I^A I^B × I^B I^B **Punnett Square:** ``` I^B I^B I^A I^A I^B I^A I^B I^B I^B I^B I^B I^B ``` **Results:** - 50% I^A I^B (Type AB blood) - both A and B antigens expressed - 50% I^B I^B (Type B blood) - only B antigens expressed The AB offspring show **codominance** because both the I^A and I^B alleles are fully expressed, producing both A and B antigens on red blood cells simultaneously.