Lesson: Lack of Dominance Biology • First Year of Secondary School

Students will be able to

• define lack of dominance as an allele not having complete dominance over another,
• recall that incomplete dominance and codominance are examples of alleles showing a lack of dominance,
• describe incomplete dominance as the merging of phenotypes to give a new, distinct phenotype and use the production of pink snapdragon flowers as an example,
• describe codominance as the simultaneous expression of alleles where both are dominant and use the AB blood group in humans as an example,
• define multiple alleles as a trait that is determined by three or more alleles where only two are present in a single organism (e.g., alleles for blood types in humans),
• interpret Punnett squares of incomplete dominance, codominance, and multiple allele crosses.