Ancestor Explorer - Ancestors with Related Persons FAQ

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Ancestors Explorer - Ancestors with Related Persons FAQ

What do the number of degrees of separation between the related parents mean? The degrees of separation are the number of steps in a genealogical tree from one related parent up to the most recent common ancestor of both related parents and back down to the other related parent. There are 2 degrees of separation between siblings, 3 degrees of separation between an uncle/aunt and a niece/nephew, 4 degrees of separation between first cousins, 6 degrees of separation between second cousins, 8 degrees of separation between third cousins, etc.

Why do ancestors with related parents cause duplicate ancestors? If the parents of an ancestor of a person were related to each other, the branches of the person’s tree relating to both of those parents will be exact duplicates starting with their most recent common ancestor and continuing back through all of that common ancestor’s ancestors. That duplication results in the person having fewer unique ancestors than expected based on the number of branches in their tree, also known as pedigree collapse. See, generally, the ISOGG wiki page on pedigree collapse.

Why is there only one most recent common ancestor for some of the instances of two related parents? If only one most recent common ancestor is listed for any instance of two related parents, that means either that (1) there is no spouse of the named commmon ancestor who is connected on Wikitree as an ancestor of the two related parents, (2) the named common ancestor had two or more spouses and the two related parents were not descended from the same spouse, or (3) the spouse of the named common ancestor of the two related parents was not within the selected number of generations from the Descendant.

Why is there more than one line for some related parents? There is a separate line for each ancestor of the Descendant whose parents were related to each other. If the Descendant is descended from more than one child of the same two related parents, there will be a separate line for each child.

Why is the number of duplicates different from the number of lines of descent from the most recent common ancestor(s) to the Descendant? The two numbers are almost entirely unrelated. Each line in the table relates to an ancestor of the Descendant whose parents were both descended from the most recent common ancestor(s). That parentage will cause there to be two copies of each of the most recent common ancestor(s) in the Descendant's tree and thus two duplicate ancestors (in addition to the two unique ancestors). If the number of generations in the tree goes back at least one generation past the most recent common ancestors, there will be two copies of each of the parents of each of the most recent common ancestor(s) and thus four additional duplicate ancestors (in addition to four additional unique ancestors) and so on. Therefore the number of duplicate ancestors listed in each line in the table depends on how many generations back from the most recent common ancestor(s) the generated list goes and how complete the ancestry of the most recent common ancestor(s) are on WikiTree. The number of lines of descent from the most recent common ancestor(s) to the Descendant, on the other hand, depends on how many ancestors of the Descendant had parents who were both descended from the most recent common ancestor(s). If there are more than two lines of descent from the most recent common ancestor(s) to the Descendant, those additional lines were the result of more than one ancestor of the Descendant having parents who were both descended from the most recent common ancestor(s).