PEDIGREE ANALYSIS

PEDIGREE ANALYSIS Diagram that shows how traits are inherited from one generation to the next Diagram tracing a particular trait through a family Used by genetic counselors to predict the likelihood of passing on a genetic disease Ex: sickle cell anemia, downs syndrome, and cystic fibrosis

DRAWING A PEDIGREE Generations are numbered with Roman numerals (I, II, III) on the left side of the pedigree Print each persons name or number neatly under their symbol Children are put in age order from left to right if given, but may be rearranged to show special relationships (ex: marriages) Provide a key for all symbols used

Key to Pedigree Symbols Male Square Female Circle Marriage Horizontal line between couple Divorce Broken horizontal line between couple Multiple marriages Numbered horizontal line between couples Death Diagonal slash over person’s symbol Siblings Vertical line from parents to a bracketed horizontal line over siblings Fraternal twins Connected by a triangular line above Identical twins Connected by a triangular line above and a horizontal line between Adoption Capital “A” inside symbol Having a trait Shaded in as specified in your key 1 2 or or A or or

SAMPLE PEDIGREE

SAMPLE PEDIGREE