Pedigree analysis is an important tool for studying inherited diseases in human families. It allows inferences about genotypes and predictions about phenotypes in offspring. A pedigree is presented showing a family with cystic fibrosis, an autosomal recessive trait. Based on the pedigree, it can be determined that individuals II-3 and III-4 must have the genotype "aa" and their parents must have each contributed an "a" allele. The other individuals could be either genotype AA or Aa.

1. The Inheritance of Single-Gene Differences Human pedigree analysis

3. Most common symbols used in creating a pedigree unaffected male unaffected female affected male affected female

4. Other common signs and symbols used in pedigree analysis

5. Sample pedigree - cystic fibrosis The roman numerals indicate the generation (I, II or III) and the numbers show birth order of children (1, 2, 3, 4 etc.) female male affected individuals

13. - Half the people in the Venezuelan village of Barranquitas are affected - A large-scale pedigree analysis was conducted including 10,000 people - Example for one particular family: Huntington’s disease: an example of AD disorder

15. Hemophilia: an example of X-linked recessive disorder

16. X-linked recessive traits ex. Hemophilia in European royalty