AP BIOLOGY

Detailed explanation-1: -A dominant allele is denoted by a capital letter (A versus a). Since each parent provides one allele, the possible combinations are: AA, Aa, and aa. Offspring whose genotype is either AA or Aa will have the dominant trait expressed phenotypically, while aa individuals express the recessive trait.

Detailed explanation-2: -Dominant alleles are represented by capital letters and recessive alleles are represented by lowercase letters. For example, blue eyes are a recessive trait and brown eyes are a dominant trait.

Detailed explanation-3: -Codominance in humans is exemplified by individuals with type AB blood. A person inheriting the alleles IA and IB will have a type AB blood because IA and IB are codominant and therefore will be expressed together.

Detailed explanation-4: -Alleles may be designated by a single capital or lower case letter (e.g., L is the symbol of Lobe eye in Drosophila) or by two, three or more letter or letter/number combinations (Wr-Wrinkled, per-periodicity). Alleles may have superscripts (wa) or subscripts (A1) or both.