Number of Direct Ancestors

[darkerhorse]

How many direct ancestors do you have at 17 generations back?

[PippoM]

Well, you should have 2^17, i.e. about 130.000 ancestors, but it's just theory.
Of course, many of them may coincide, i.e. you might have the same ancestors in different branches of your tree.
For instance, a couple of my GGGParents were first cousins; so, from their Gp's on, there are two equal subtrees in my tree.
In my wife's tree, this situation is much more common.

[darkerhorse]

Just to clarify, I don't mean cumulative, I mean just at that one level.

For example, at one generation back you have two (parents), at two generations back you have four (grandparents), not six (parents plus grandparents), and so forth.

Are you saying at seventeen generations back you would have 130,000 14x great-grandparents!

[MarcuccioV]

Barring any repeats, the answer is 131,032.

I, like you, only have 62 4GGP's. I'm sure many people have similar situations somewhere in their trees...

[darkerhorse]

I just found the math - you and Pippo are right.

[darkerhorse]

For some/many people, only one of the 131,032 would carry their surname?

[MarcuccioV]

For some/many people, only one of the 131,032 would carry their surname?

Surnames might be an iffy subject. First of all, surnames are in the big picture of things, fairly recent. I know in Germany they were still grappling with the idea in the 1800's in some places. Most surnames in Italy seem to have been developed by a physical trait, location, situation, etc, so when you really start digging deep the waters really get muddy...

In my family line there is a branch with a surname of "Tessitori" (weaver). A distant ancestor was "Giorgio Tessitori". His son decided to change the family surname to "Giorgi". And so it goes...

[darkerhorse]

What I mean is only one forebearer comes from your direct surname line.

We tend to identify with ancestors of our surname line because of the commonality of surname, but we are no more that one line than any we are any other line, if I understand genealogy correctly.

An extreme example is the Kennedy clan. Among them you had to have that surname to be considered "royalty". I guess, in part, it's the male bias. Probably true of many families.

[rp76226]

2+4+8+16+32+64+128+256+512+1,024+2,048+4.096+8,192+16,384+32,768+65,536+131,072 = 262,142