The pedigree is a diagram that shows family history using standardized symbols. It shows the relationships between family members and indicates which individuals have certain genetic traits, these traits are usually pathogenic like hemophilia, or they can be harmless traits like the color of eyes. The pedigree also shows the inheritance patterns of the traits depicted on it.
Each individual is represented by a symbol:
A square represents a male and a circle represents a female:
In this diagram, the generations are ordered in rows. Each generation is indicated with Roman numbers and each individual within the same generation is identified by Arabic numbers.
Relationships on a pedigree are depicted with lines.
Parents are connected by a horizontal line, then a vertical line indicates their offspring. Siblings are connected by a horizontal sibship line and are ordered from left to right according to their birth:
The relationship line indicates that the individuals had descendants.
The line of descent indicates which individuals of the next generation are their offsprings.
The sibling line indicates which individuals have the same parents.