Pedigrees BIO 3.2.2 Predict offspring ratios based on a variety of inheritance patterns (including dominance, co-dominance, incomplete dominance, multiple alleles, and sex-linked traits).

Pedigrees Geneticists use pedigrees to trace diseases or traits through families. Pedigrees are diagrams that reveal inheritance patterns of genes.

Standard Symbols: female male (shaded) has trait or disease (half shaded) known carrier (not shaded) does not have trait or disease deceased Mating or married parents children

How to Label a Pedigree Is III-4 a male or female? Is II-5 affected or unaffected?

Determining Inheritance Pattern If trait or disease shows up in all generations, it is probably dominant.

If the trait or disease usually skips generations, it is probably recessive. If carriers are shown, or if a child has it and both parents do not, it is DEFINITELY recessive.

Cystic Fibrosis – recessive or dominant?

If a trait is X-linked recessive it will usually only show up in males and will skip generations

This is one messed up pedigree!

Polygenic Inheritance Polygenic characters, such as skin color, are controlled by two or more genes. Complex characters, such as polygenic traits, are influenced by both genes and environment.