I was pondering my ancestry a couple days ago. Specifically I began wondering how many 10th great grandparents I have. Then I began thinking about how many 15th and 20th great grandparents, etc. I began with 2 parents, 4 grandparents, 8 great grandparents, etc. Now add the average generational gap to the scenario (average generational gap is normally considered somewhere between 25 and 35 years). This thought process revealed very interesting numbers. Let me show you what I found:
10th great grandparents = 4,096 (birthdates around 1585 to 1675 AD)
15th great grandparents = 131,072 (” ” 1410 to 1550 AD)
20th great grandparents = 4,194,304 (” ” 1235 to 1425 AD)
25th great grandparents = 134,217,728 (” ” 1060 to 1300 AD)
30th great grandparents = 4,294,967,296 (” ” 885 to 1175 AD)
Yes, that is billions at the 32nd generation (30th great grandparents). I have seen several world population estimates, but most seem to think that around 1200 AD there were 400 to 500 million people on the earth at that time. Based on the numbers I present above, this means somewhere between the 25th and 30th great grandparents, we should all have not just one, but complete common ancestors. No, this is not a proven science project, but rather just a simple look at numbers. Very intriguing!
2 users commented in " Are we related? "
Follow-up comment rss or Leave a TrackbackJust bear in mind that many of your 30th great grandparents are undoubtably represented multiple times in your family tree. Once you get back even just a couple of centuries, it is very common for people to have the same ancestors represented through genealogical lines, especially because people often lived in small, tight-knit communities.
One set of my fourth great grandparents through one line are also my fourth great grandparents through another line. Another set of ancestors are directly linked to me through three different lines, but at different generational levels. Regular researchers know how common this kind of thing is.
We have lots of research going back hundreds of years on several lines. But there are far more blank spaces than completed spaces the further back I go. Undoubtably, many of these blank spaces would be filled by people that are already represented in my family tree.
In other words, it is still likely that the 400-500 million population estimate is relatively accurate.
Absolutely agree. The equation I am trying to demonstrate, though, is that the numbers demonstrate the concept that we are all likely related through multiple lines at least by 1200 AD (almost guaranteed by the 32nd generation). I have a cousin, Bev, in town who I have identified as a cousin 4 times so far through distinct lines (3rd, 4th, 5th, and 7th). Interestingly my wife is her 4th cousin, too. Extra neat. Certainly is a small world we live in.