Relationships between alleles of the ABO blood group system can be explained by:
Correct answer: A. Complete dominance and Co-dominance
- A. Complete dominance and Co-dominance
- B. Incomplete dominance and Co-dominance
- C. Over dominance and Incomplete dominance
- D. Complete dominance only
Explanation
The ABO blood group system is a classic example of both complete dominance and co-dominance. Alleles A and B are completely dominant over allele O. This means that if either A or B is present with O, the phenotype will be A or B, respectively. However, when both A and B alleles are present, they exhibit co-dominance, meaning that both alleles are equally expressed, resulting in the AB blood group. Options B, C, and D are incorrect as they fail to accurately describe these genetic relationships.
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Mendel's laws explain segregation, independent assortment and the prediction of genetic ratios using alleles, genotypes and phenotypes. The chapter also covers linked genes, recombination and crossing over during meiosis, then applies pedigree reasoning to X-linked recessive traits, which show different inheritance patterns in males and females.
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