PEDIGREE

a record of ancestry or purity of breed. Studbooks (listings of pedigrees for horses, dogs, etc.) and herdbooks (records for cattle, swine, sheep, etc.) are maintained by governmental or private record associations or breed organizations in many countries. In human genetics, pedigree diagrams are utilized to trace the inheritance of a specific trait, abnormality, or disease. A male is represented by a square or the symbol , a female by a circle or the symbol . Mating is shown by a horizontal line (marriage line) connecting a male symbol and a female symbol; offspring symbols are connected in a row (sibship line) beneath the mated pair. The offspring symbols appear from left to right in the order of birth and are connected to the marriage line by a vertical line. Possession of the character under study is shown by a solid or blackened symbol, and absence is shown by an open or clear symbol. Multiple births are designated by joining the individual symbols to the same point on the sibship line. Siblings not shown as individual symbols are indicated by a number within a large symbol for each sex.