The original question regarding which term to use was posted to attain an English (American) version of a foreign language term which translates somewhat to "ancestor loss." Pedigree Collapse was the term used by the larger organizations of genealogist, and in those old anthropology articles quoting demographer K. Wachter, and Alex Shoumatoff ("The Mountain of Names") who also quotes science author Guy Murchie, apparently by anthropologists and geneticists. I did see reference to "of the half blood" used by the New England Historical and Genealogical Society, to represent the lesser loss of ancestors by the common populations as opposed to Royal lineage which have a high percentage of "collapse." To me: -Six of one, half dozen of another.- Of the ones Jeff mentions, confluence seems the more logical, evoking a pleasant mental image with the river analogy. I think the collapse term was to emphasize the great loss of numerical ancestors, and point out that our family tree model can't be an inverted p yramid. They provide the graphic diagram of a diamond shaped genealogy, where ego is the bottom and their proverbial Adam and Eve are the top. The collapse happens and progresses in similar exponential fashion to the buildup. Some of our diamonds have differing dimensions, but obviously we all have them or the scientists should have to tell us that the population of the earth was much larger (some 281 trillion) in past than it is now. Royal diamonds must have a much sharper (acute) top than common populations! OUCH :-) Di <--- thinking about rivers of diamonds... LOL j/k == In a message dated 02/2/14 9:50:31 PM, ScismGenie@aol.com writes: << NOT pedigree collapse, but I have seen it called "confluence", "A close knit family", and "circular Genealogy". Jeff >>