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Pedigree collapse is a term created by Robert C. Gunderson to denominate the collapse of the family trees caused either by close cousin marriages or distant cousins unknowingly getting married.
If we assume that there is a new generation each 25 years, over 600 years a single person can have up to 224 or roughly 16 million possible ancestors. But if go back another 600 years (to 800AD), that will get us 248. That would be 281.5 trillion ancestors, far more people than have existed throughout the history of humanity. An ancestor is a parent or (recursively) the parent of an ancestor. ...
The catch is that ancestors along the way married their cousins, often without knowing it but in many cases intentionally. This is pedigree collapse; the closer the cousin, the bigger the percentage of the collapse. Of course the worst case is when two siblings got married (think royalty-wise for instance) when it is a 50% collapse. With a first cousin, it is a 25 percent collapse, and so on.
In some cultures, cousins were encouraged or required to marry to keep kin bonds, wealth and property within a family. Among the royalty, the frequent requirement to only marry other royals resulted in a reduced gene pool where most individuals had extensive pedigree collapse. Alphonso XII, for example, had only eight great-great-grandparents instead of the usual sixteen. Isolated populations such as remote islanders represent extreme examples of pedigree collapse but the ordinary tendency to marry those within easy walking distance along with the relative immobility of the population before modern conveniences meant that most marriage partners were distantly related. Even in America, the tendency of immigrants to marry among their ethnic, language or cultural group produces many cousin marriages. Greg Flesch is a guitarist and musician, best known for his work with the rock bands Daniel Amos and The Swirling Eddies (credited as Gene Pool). Flesch also works in the Atmospheric Laser Spectroscopy Group at the Jet Propulsion Laboratory in Pasadena, California, writing software for the groups tunable...
Alfonso XII of Spain (November 28, 1857 _ November 25, 1885), was king of Spain, reigning from 1875 to 1885, after a coup detat restored the monarchy and ended the ephemeral First Spanish Republic. ...
Demographer Kenneth Wachtel estimated that for a typical English child of the mid-20th century, at the time of Columbus, 95 percent of his ancestors would have been different individuals and 5 percent duplicates. At the time of the Black Death, an average of 70 percent would have been duplicates. Christopher Columbus For information about the film director, see the article on Chris Columbus. ...
Illustration of the Black Death from the Toggenburg Bible (1411). ...
The maximum number of ancestors for most people is likely to occur around 1200 AD. Some geneticists believe that everybody on earth is at least 50th cousin to everybody else. Genetics (from the Greek genno γεννώ= give birth) is the science of genes, heredity, and the variation of organisms. ...
See also
Inbreeding is breeding between close relatives. ...
External links
Source - The Mountain of Names by Alex Shoumatoff (1985).
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