1. PEDIGREE ANALYSIS

2. 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

3. 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

4. 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

5. SAMPLE PEDIGREE

6. SAMPLE PEDIGREE