Lab Activity Blood Type Pedigree Mystery -

Her partner Leo leaned in. On the chart: Grandparents Ana and Carlos (both type A), their three children—Elena (type O), Marco (type AB), and Luis (type A)—and Luis’s two kids, Sofia (type A) and Diego (type B).

“That’s your lab task,” Dr. Reeves smiled. “Using only the pedigree and a fresh blood sample from Julian, determine if he could be Ana’s son—and whether the estate should accept or reject his claim.” lab activity blood type pedigree mystery

Carlos was type A (AO)—so he could have been Julian’s father biologically, but the timing was wrong. The real shock came when Marco secretly submitted a DNA test: he and Julian shared a Y-chromosome marker that Carlos didn’t have. Julian’s father was not a stranger—he was Carlos’s own brother, long presumed dead, who had a brief relationship with Ana before she married. Her partner Leo leaned in

The estate granted Julian a share—not because of the blood type pedigree alone, but because the mystery of the pedigree led them to ask the right questions. And in forensics, asking the right question is half the solution. Would you like a printable student worksheet to accompany this story, including data tables and analysis questions? Reeves smiled

“If Julian is truly Ana’s son,” Maya said slowly, “and Ana was AB at the time of his birth, Julian cannot be type O.”

Dr. Reeves appeared beside them, holding a manila folder. “The mystery is him .” She tapped a new figure connected to the family by a dotted line: a man named Julian Reyes, claiming to be Ana’s biological son from a brief relationship before her marriage. “Julian says he was given up for adoption at birth. Now he’s petitioning the family estate. Genetic testing is pending, but he’s offered to prove his claim with a simple blood test today.”

The late afternoon light slanted through the lab windows as Maya pinned the last pedigree chart to the corkboard. “Okay, team,” she announced, uncapping a set of blood typing trays. “This is the Martinez family case.”