Have you ever thought about how many ancestors one person could possibly have? Mathematically speaking, taking one’s family tree out thirty generations would result in about a BILLION ancestors. Taking it out forty to fifty generations would result in approximately a TRILLION ancestors — more people than have EVER lived on the earth!
Of course, that has never happened (or ever will), but why is that? The answer is pedigree collapse.
Pedigree collapse is defined as “the phenomenon in which ancestral inbreeding causes the number of a descendant’s ancestors to be smaller than that predicted by a binary tree:where n represents number of generations.” (Wiktionary)
Researchers and theoreticians have hypothesized that historically eighty percent of all marriages have been between second (or closer) cousins. Some geneticists also estimate that every person on planet earth is at least a fiftieth cousin to everyone else.
Family researchers may not see pedigree collapse for several generations, but inevitably it will pop up as you climb the family tree. For my own family (starting from my father), it occurs in the fourth generation when first cousins, John Clayton Hall and Catherine Kate Hall, married in 1879.
As the chart (click to “embiggen”) shows, John Clayton’s father was John Oxly and he was a brother to Catherine’s father Eli. Consequently, for the sixth generation of the Hall line pedigree collapse occurs because there are shared grandparents for John C. and Catherine — Joseph Hall and Mary Catherine Matlock.
I haven’t come across any other instances of pedigree collapse in the Hall line . . . yet. There is, however, an anomaly of sorts on the Strickland side. Mary Angeline Hensley was both my great-great grandmother and my great-great-great aunt (if my calculations are correct). There’s a story … for another article someday.
Have a GREAT day . . . someday it will be HISTORY!