Orderly diagram of a family’s genetic traits Notes: Pedigrees Orderly diagram of a family’s genetic traits

A pedigree shows… relationships, sex, genotype & phenotype of each member if an allele is dominant or recessive if an allele is autosomal or sex-linked

Symbols Circle = female Square = male Horizontal line = parents Vertical line = children Symbol w/line through it = dead

More symbols Half-Shaded = heterozygous not affected (recessive disorder) Completely darkened = homozygous affected Half-Darkened = heterozygous affected (dominant disorder)

Rule #1- Autosomal Dominant In general, males & females equally affected NO skipping generations Trait is expressed if allele is present

Rule #2 – Autosomal Recessive In general, males & females equally affected Can skip generations Both parents are carriers Trait is expressed only if homozygous

Rule #3 - Autosomal In general, males & females equally affected Father-son transmission of trait

Rule #4 – Sex-linked recessive In general, more males are affected than females If mom is carrier  sons are affected, not daughters If dad is affected  daughters are carriers NO dad-son transmission NO male carriers

Try this one Autosomal dominant

Dominant - Autosomal

Recessive - Autosomal

Recessive, X-linked

Autosomal recessive

Recessive - Autosomal

Dominant - Autosomal

Recessive, X-linked

Autosomal recessive

X-linked recessive