Pedigrees

A pedigree is a diagram or record that shows the lineage or ancestry of an individual, organism, or trait across multiple generations. In genetics and animal breeding pedigrees are used to track parentage and relatedness, while in human genealogy they document family lines and descent. The word pedigree derives from French and Latin roots meaning descent and lineage, and modern usage dates to the 19th century when breeders and scientists formalized charts of ancestry.

In genetics, pedigrees are used to study inheritance patterns, identify carriers, and estimate the probability that a trait will appear in offspring. Standard conventions depict sexes with squares for males and circles for females, with horizontal lines for mating and vertical lines for children. Shading or symbols indicate affected individuals, known carriers, or other statuses, and generations are labeled to show lineage over time.

Constructing a pedigree requires reliable history or breeding records and careful organization into generations. Pedigrees help analyze autosomal dominant, autosomal recessive, and X-linked traits; they support carrier testing and risk assessment. They also support calculations of kinship and, in breeding programs, inbreeding coefficients.

Limitations include incomplete or inaccurate data, small or broken lineages, unknown parentage, and non-biological relationships that can complicate interpretation. Despite these limitations, pedigrees remain a fundamental tool in human medical genetics, veterinary breeding, and conservation genetics for managing traits, heritable diseases, and genetic diversity.