Pedigree Worksheet

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Genetics Pedigree Worksheet
A pedigree is a chart of a person’s ancestors that is used to analyze genetic inheritance of certain traits
– especially diseases. The symbols used for a pedigree are:
female, unaffected
male, unaffected
female, affected
male, affected
--------------------------------- -- -----------------------------In humans, albinism is a recessive trait. The disorder causes a lack of pigment in the skin and
hair, making an albino appear very pale with white hair and pale blue eyes. This disorder also
occurs in animals, a common albino found in a laboratory is the white rat. The pedigrees below
trace the inheritance of the allele that causes albinism.
A means “not albino” (dominant)
a means “albino” (recessive)