Genealogical charts are diagrams that illustrate the physical characteristics and lineage of a particular gene or organism and its ancestors in a generation. They are commonly referred to as family trees, and in terms of genetics, they are used to show the inheritance of a health trait or condition through generations of a family. The family tree will indicate which individuals have a trait or traits of interest, and it can also be used to establish how likely a child is to have a particular disorder or condition. The word pedigree is derived from the Anglo-Norman French phrase 'pie de grue' or 'crane foot', which is thought to be due to the thin leg and foot of a crane resembling the typical lines and divided lines (each of which leads to different descendents from a parental line) found on genealogical charts.
Family trees are often constructed after a family member has been identified as suffering from a genetic disorder. They can help determine how a trait or condition can be transmitted from generation to generation and what may accompany it. However, it is not possible to confirm sexual attachment from genealogical graphs, since autosomal traits could generate the same results. In the practice of selective animal husbandry, particularly fantasy animals and livestock, including horses, genealogical charts are used to trace animal ancestry and help plan appropriate breeding programs to improve desirable traits.
In England and Wales, pedigrees are officially registered at the College of Arms, which has records dating back to the Middle Ages, including pedigrees collected during itinerant research conducted by its heralds during the 16th and 17th centuries. Family tree analysis using the principles of Mendelian inheritance can determine if a trait has a dominant or recessive pattern of inheritance. This type of analysis can be used to identify potential carriers of genetic disorders in families with known genetic disorders. It can also be used to identify potential carriers in families with no known genetic disorders.