Lecture 8: Pedigree Analysis

Pedigree analysis

Determine pattern of inheritance of traits in humans and animals

Predict possible genotypes and phenotypes of future offspring

More common in humans

Experimental mating not made (not ethical)

Few offspring available to study

Info from family trees or pedigrees (history)

Symbols

Square unshaded: Male unaffected

Square shaded: Male affected

Circle unshaded: Female unaffected

Circle shared: Female affected

Horizontal line: Mating

Vertical lines: birth order (1st on left), siblings

Affected with trait: Phenotype expressed

Autosomal dominant

Shows ups in all generations

Females and males equally affected

Offspring have affected parents

Unaffected homozygous recessive

Autosomal recessive

Parents heterozygous can produce offspring with trait

Affected offspring have unaffected parents

Females and males equally affected

Affected homozygous

Skips generations

X-linked recessive traits

May skip generations

Never passed from father to son

Males affected more than females