Pedigree Analysis – AP Bio

This worksheet was designed for AP Biology students studying genetics. Students are not given the inheritance pattern for diseases like Marfan Syndrome and Charcot-Marie-Tooth disease. Students must determine whether the disorder is dominant, recessive, or sex-linked from the diagram.

Questions ask students to provide reasoning for their choices and they must indicate the genotypes of the individuals on the diagram.

There are simpler pedigree practice worksheets for regular biology. These are smaller diagrams where students are given the inheritance pattern. I usually tell students to work there way backwards from individuals in the family that display the phenotype being studied.

The shaded diagrams represent those individuals. Another tip I give students to help remember diagram icons is that the males are square because they are “blocky” and the females are circles because they are “curvy.”


After they are confident in analyzing pedigrees, I often show them a historic pedigree of hemophilia in the royal family that originated from Queen Victoria. This is also a good time to discuss why close family marriages (like first cousins) can result in a higher risk of inheriting these types of diseases.