Topic 30: Pedigrees

Question 1

What do the symbols in a pedigree represent?

Answer 1

Symbols
Circle: Represents Female
Square: Represents Male
Horizontal line: Married or Mated
Verticle line: Children from both parents
Colored Circle: Affected female by trait
Colored Square: Affected Male by trait
Roman Numerals: Generations

Question 2

Use a pedigree to determine how a trait is inherited: autosomal dominant, autosomal recssive, x-linked recessive, x-linked dominant.

Answer 2

Using a pedigree to determine how a trait is inherited
Autosomal means a gene that is part of the non-sex chromosomes.

Autosomal Dominant: Traits cannot skip a generation because its dominant. Individual with a trait must have a parent with the same trait. Parents with trait can have a child without the trait.
Autosomal Recessive: Traits can skip generations and appear in other generations. Parents without the trait can have a child with the trait.
X-linked: Involved in sex chromosomes, present in males.
X-linked Recessive: X-linked Recessive can be passed down to males and also females as carriers.
X-linked Dominant: Traits are passed down in every male child.

Question 3

Analyze a pedigree to determine the genotype of individuals

Answer 3

-View pedigree
- search for any traits
- examine ifts x-linked or autosome
- notice if its been passed down in every generation or only a few generations