Download Pedigrees - Solon City Schools

Pedigrees
Pedigrees
• A pedigree is a diagram of family relationships that
uses symbols to represent people and lines to
represent genetic relationships.
• These diagrams make it easier to visualize
relationships within families, particularly large
extended families.
• Pedigrees are often used to determine the mode of
inheritance (dominant, recessive, etc.) of genetic
diseases.
Pedigrees
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Squares represent Males
Circles represent Females
Horizontal lines connecting a male and female represent mating
Vertical lines extending downward from a couple represent their
children
• Oldest individuals are found at the top and youngest on the
bottom
Pedigrees
• Completely shaded in individuals posses the
trait
• Half shaded in individuals are carriers of the
trait
Complete the handout
Complete the handout
Pedigree Problems
• Brown eyes are dominant to blue eyes. John has
blue eyes. His parents are heterozygous brown
eyed individuals. When John was married, they
had 3 children. The oldest girl had brown eyes, the
middle son had blue eyes, and the youngest
daughter had brown eyes. When the youngest
daughter was married, she had twins. The male
had blue eyes and his twin sister was homozygous
for brown eyes. Construct a pedigree for the
following individuals. Please write the genotypes
where possible.
Pedigree Problems
• The ability to taste PTC is controlled by a dominant
gene (T). A woman nontaster marries a male taster.
They have three children. The two boys were able
to taste the paper and their younger sister was a
nontaster. All the grandparents were tasters.
Construct a pedigree of this family. (Please let
nontasters (tt) be the shaded individuals)