In most classroom blood type pedigree mysteries, the "secret" to the answer key lies in identifying which parent has a recessive Type O (ii) gene or an AB (IAIB) genotype. Since blood typing follows codominance and standard Mendelian genetics, you can solve any version of this lab by following a specific logical flow. 🩸 The Universal Answer Key Logic
It turns out that John's parents were both carriers of the B allele. John's mother had blood type B, and his father had blood type A. This means John inherited a B allele from one of his parents, making his genotype AB (not AA or AO).
ABO system basics
1. Analyze the Father’s Genotype:
Here is the updated pedigree:
The Blood Type Pedigree Mystery is an educational lab activity—often found on platforms like TPT and Course Hero—where students solve a theft using genetics. Key Features of the Activity
Introduction
The mystery is solved by identifying the individual whose genotype allows for both Type A blood and attached earlobes. Pedigree Chart diagram to help visualize the family's inheritance?