Heredity

3.2.2

Predict offspring ratios based on a variety of inheritance patterns (including dominance, co-dominance, incomplete dominance, multiple alleles, and sex-linked traits).

Unpacking:

• Interpret Punnett squares (monohybrid only) to determine genotypic and phenotypic ratios. Understand that dominant alleles mask recessive alleles.

• Determine parental genotypes based on offspring ratios.

• Interpret karyotypes (gender, and chromosomal abnormalities).

• Recognize a variety of intermediate patterns of inheritance (codominance and incomplete dominance).

• Recognize that some traits are controlled by more than one pair of genes and that this pattern of inheritance is identified by the presence of a wide range of phenotypes (skin, hair, and eye color).

• Interpret autosomal inheritance patterns: sickle cell anemia including the relationship to malaria (incomplete dominance), cystic fibrosis (recessive heredity), and Huntington’s disease (dominant heredity).

• Solve and interpret codominant crosses involving multiple alleles including blood typing problems. (Blood Types: A, B, AB and O and Alleles: IA, IB, and i). Students should be able to determine if parentage is possible based on blood types.

• Understand human sex chromosomes and interpret crosses involving sex-linked traits (color-blindness and hemophilia). Students should understand why males are more likely to express a sex-linked trait.

• Interpret phenotype pedigrees to identify the genotypes of individuals and the type of inheritance.