Pedigree chart
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Pedigree-chart-example.png
A pedigree chart is a chart which tells you all of the known phenotypes for an organism and its ancestors, most commonly humans, show dogs, and race horses.
The word pedigree is a corruption of "pied de gru" or crane's foot, because the typical lines and split lines (each split leading to different offspring of the one parent line) resemble the thin leg and foot of a crane.
In an animal pedigree chart, a female is represented with a circle and a male with a square, and is organized much like a family tree. All those individuals' shapes with an affected or disease characteristic are coloured in, all those without that characteristic are left unfilled. A disease may be recessive or dominant. Organisms known to be heterozygous are half coloured in, half not.
Pedigree charts are also a common tool in human genealogy studies. For the aristocracy, to whom these things are of great importance, their pedigrees are (in England and Wales) officially recorded in the College of Arms, which has collections of pedigrees going back to the middle ages, including pedigrees collected during roving inquiries by the heralds into the nobility and gentry during the sixteenth and seventeenth century visitations. Such pedigrees continued to be registered and kept up to date on a voluntary basis but they are not accessible to the general public without payment of a fee.
More visible, therefore, are the pedigrees recorded in published works, such as Burke's Peerage and Burke's Landed Gentry in the United Kingdom and, in continental Europe by the Almanach de Gotha. Due to space considerations, however, these publications typically use a narrative pedigree, whereby relationships are indicated by numbers (one for each child, a different format for each generation) and by indentations (each generation being indented further than its predecessor). This format is very flexible, and allows for a great deal of information to be included, but it lacks the clarity of the traditional chart pedigree.
New pedigree techniques have been developed for the world wide web, including the one discussed here (http://computing.dcu.ie/~humphrys/FamTree/hyper.html).