Pedigree Collapse, also known as Implexus, occurs when distant cousins inter-marry, and parts of your family tree are duplicated. Since the number of your ancestors doubles every generation, and there are more humans alive than any period history, it is inevitable that we share the same ancestors, and we are all in a sense distant cousins.
If you go back far enough up your family tree, you will find certain persons reappearing in different parts of the tree. When that happens, entire sections are repeated, and the pedigree "collapses".
A simple example is illustrated here, with first-cousins marrying.
|Ancestor view: "Michael Smith" and "Priscilla Maher" are first cousins, they share the same grandparents.|
|Descendant View: "Abner Smith" and "Mehitabel Smith" are brother & sister, their children marry.|
Progeny's Charting Companion gives you the option of showing every instance of the identical part of the tree, or only showing it once. This option is called "Cousin Smart", and is available for each of the twelve different genealogical charts that we offer.