Name: _________________________________ Date: _________________ Period: ______ Mod A – Cells & Heredity Lesson 2.5 Page 20 Fry 2017 Pedigree Introduction A pedigree is a visual chart that depicts a family history or the transmission of a specific trait. They can be interesting to view and can be important tools in determining patterns of inheritance of specific traits. Pedigrees are used primarily by genetic counselors when helping couples decide to have children when there is evidence of a genetically inherited disorder in one or both families. They are also used when trying to determine the predisposition of someone to carry a hereditary disease for example, familial breast cancer. The Components of a Pedigree: Squares are used to indicate males in a family. Circles are used to indicate females. If the individual is “affected" by the trait (dominant or recessive) we darken the shape. A line between a male and a female indicates a marriage or union. A line drawn down from the marriage line indicates offspring. Sometimes, you will see some shapes filled in only half way - this notation indicates a hybrid (heterozygous) or carrier of the trait.
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2.5 Pedigree Practice Packet - Oxford Area High School...A pedigree is a visual chart that depicts a family history or the transmission of a specific trait. They can be interesting
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Mod A – Cells & Heredity Lesson 2.5 Page 21 Fry 2017
Pedigree Practice
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.
1. Given the following genotypes, describe the phenotypes (normal or albino).
AA = ________________________________
Aa = ________________________________
aa = ________________________________
Fill out the blanks on the pedigree to the right.
1. How many children does this family have?
_______
2. What are the sexes of the children?
_______
Fill out the blanks of the pedigree to the right (AA,