A key point to remember is that the (the "+" or "-" in blood typing). They are inherited independently.
Before diving into the mystery, students must master the unique inheritance pattern of human blood types. The ABO blood group system is an excellent teaching tool because it demonstrates both and codominance . The ABO Alleles
In the updated curriculum file, Baby X actually belongs to a third lineage or indicates a mutation/error in data recording, or Mr. Smith's family tree reveals recessives. Let's look at the standard updated key where Baby X belongs to the Smiths (if they are both heterozygous , they can make an baby) and Baby Y belongs to a third family.
Always begin by filling in the genotypes of individuals whose phenotypes reveal their exact genetic makeup: Anyone with blood must be . Anyone with Type AB blood must be IAIBcap I to the cap A-th power cap I to the cap B-th power . Anyone with Rh-negative blood must be . Step 2: Work Backward from Type O Offspring If a child has Type O blood ( ), they must receive one allele from their mother and one allele from their father. lab activity blood type pedigree mystery answer key upd
allele as the definitive proof for why he cannot have a Type O child. If you want to tailor this guide, let me know:
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Medical records of the family's blood types have been recovered. Students must reconstruct the pedigree chart, fill in the missing genotypes, and determine if Charles is genetically linked to the family. The Recovered Medical Data Arthur Pendelton (Grandfather - Deceased): Type AB Eleanor Pendelton (Grandmother): Type O Generation II (Children & Spouses): Beatrice (Arthur & Eleanor's Daughter - Deceased): Type A Edward (Beatrice’s Husband): Type B David (Arthur & Eleanor's Son): Type B Grace (David’s Wife): Type A Generation III (Grandchildren): A key point to remember is that the
Two babies were born at the same time, but in the chaos, they were mixed up. The lab's purpose is to look at the blood types of the parents and the babies to determine which baby belongs to which parents using a pedigree chart. II. Background Knowledge To solve this mystery, students must understand:
Many updated labs include the Rh factor (+/−) as an additional layer. The key explains that Rh-positive is dominant (Rh+/Rh+ or Rh+/Rh−) and Rh-negative is recessive (Rh−/Rh−). This simulates more realistic forensic genetics, where multiple markers increase certainty.
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: Students must draw a family tree for Joseph, Rita, and their descendants, marking generations with Roman numerals and individuals with specific symbols.
Below is the definitive analysis of the Pendelton family lineage. Use this updated key to grade student worksheets or guide struggling lab groups. Generation I Analysis Phenotype is Type AB . His genotype must be IAIBcap I to the cap A-th power cap I to the cap B-th power . Eleanor (I-2): Phenotype is Type O . Her genotype must be . Generation II Analysis IAIBcap I to the cap A-th power cap I to the cap B-th power ) and Eleanor ( ) can only pass an IAcap I to the cap A-th power IBcap I to the cap B-th power allele from Arthur, and must pass an