A and B alleles are codominant. If an individual inherits both, their blood type is AB. The O allele is recessive. An individual only has Type O blood if they inherit two O alleles. Therefore, the possible genotypes are:Type A: AA or AOType B: BB or BOType AB: ABType O: OO Decoding the Pedigree Mystery
To solve the mystery, students must first understand the genetic rules governing blood types. Unlike simple dominant-recessive traits, the ABO system involves and codominance . Genetics of blood type: inheritance and compatibility
Since Joseph’s specific genotype is often a "mystery" in the lab, use his children’s blood types to deduce it. If Rita is Type AB ( cap I to the cap A-th power cap I to the cap B-th power ) and they have a child who is Type O ( lab activity blood type pedigree mystery answer key upd
| | O | O | | --- | --- | --- | | A | AO | AO | | A | AO | AO |
Parents' possible genotypes
Blood type is determined by multiple alleles (forms) of the ABO gene. The ABO gene codes for an enzyme that modifies the carbohydrate molecules on the surface of red blood cells. The three main alleles are:
Here are the answers to the key analytical questions that accompany the lab: A and B alleles are codominant
She possessed the incredibly rare Bombay phenotype. Because she lacked the ability to produce the H-antigen—the chemical base required to make A or B antigens attach to red blood cells—her blood tests always defaulted to type O. She was a genetic chameleon. She carried the functional B gene, but it was masked, hidden in plain sight for her entire life.
A pedigree allows us to trace a trait through generations to figure out if an individual is homozygous or heterozygous for a trait, which is crucial for identifying how recessive traits can "hide" in a family. 📝 Answers to Analysis Questions An individual only has Type O blood if
Use this updated data table to cross-reference phenotypes and determine exact genotypes. Family / Individual Character Name Phenotype (Blood Type) Confirmed Genotype Mr. John Smith IAicap I to the cap A-th power i Mrs. Mary Smith IBicap I to the cap B-th power i The Davis Family Mr. Robert Davis IAIBcap I to the cap A-th power cap I to the cap B-th power Mrs. Susan Davis The Jones Family Mr. David Jones Mrs. Karen Jones IAicap I to the cap A-th power i The Children IAIBcap I to the cap A-th power cap I to the cap B-th power IBicap I to the cap B-th power i RRcap R cap R IBicap I to the cap B-th power i The Estate Mystery Grandfather (Deceased) IAIBcap I to the cap A-th power cap I to the cap B-th power , Genotype varies Grandmother Claimant (Grandchild?) Part 3: Step-by-Step Pedigree Analysis & Answer Key Problem 1: Matching the Mixed-Up Children
Blood Type Pedigree Mystery Analysis | PDF | Genotype - Scribd