1. Pedigree Analysis

2. Generations appear in rows, indicated by a successive Roman numeral
Individuals in each family are listed across the rows, in birth order
Males are squares, females are circles
Affected individuals are shaded, unaffected individuals are not shaded (in sex-linked traits, carriers can be half-shaded)
Pedigree Structure

3. Types of Genetic Disorders
Pedigrees are usually used to track genetic disorders
Two types of genetic disorders:
Autosomal
On one of 22 pairs of non-sex chromosomes
Sex-Linked
On the 1 pair of sex chromosomes (XX or XY)
Types of Genetic Disorders

4. Examples of Autosomal Disorders
Autosomal & dominant
Marfan syndrome
Huntington disease
Autosomal & recessive
PKU (Phenylketonuria)
Sickle-cell disease
Tay-Sachs disease
Examples of Autosomal Disorders

5. Examples of Sex-Linked Disorders
Sex-linked & dominant
Rett syndrome (lethal in males)
Sex-linked & recessive
Duchenne muscular dystrophy
Fragile X syndrome
hemophilia
Examples of Sex-Linked Disorders

6. Pedigrees can be analyzed to determine if a trait is:
Autosomal & dominant
Autosomal & recessive
Sex-linked & recessive
(Sex-linked & dominant – very rare)
Inheritance Patterns

7. Hints Recessive traits can skip generations
Sex-linked traits affect males more frequently than females
Hints

8. Can you determine the genotype of the individual shown?