# What's the furthest back a person alive today could trace their ancestry (reliably)

**URL:** <https://boards.straightdope.com/t/whats-the-furthest-back-a-person-alive-today-could-trace-their-ancestry-reliably/996850>\
**Category:** Factual Questions\
**Created:** [January 30, 2024, 12:45am UTC](https://boards.straightdope.com/t/whats-the-furthest-back-a-person-alive-today-could-trace-their-ancestry-reliably/996850 "2024-01-30T00:45:10Z")\
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**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\
**Post date:** [January 30, 2024, 1:15am UTC](https://boards.straightdope.com/t/whats-the-furthest-back-a-person-alive-today-could-trace-their-ancestry-reliably/996850/5 "2024-01-30T01:15:03Z")

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> [@MC\_Lovecraft](#):
>
> It depends what you mean by tracing the lineage. If you mean being able to identify every link in the chain, I really have no idea, but every living person _can_ be traced back along the matrilinear line to a single individual ancestor, known as “[Mitochondrial Eve](https://en.wikipedia.org/wiki/Mitochondrial_Eve#)” who lived between 100-230 thousand years ago.

You have to go back a long way to find a common mitochondrial ancestor, because mitochondrial DNA is inherited only through the maternal line. But with genealogical ancestry (which corresponds to nuclear genomic DNA) you have two parents, so your number of ancestors doubles each generation as you look back, and you quickly get overlapping ancestry.

So the most recent genealogical common ancestor of all modern humans was much more recent, probably around 2,300 years ago. And at around 5,000 years ago all modern humans have identical ancestry: everyone then alive was either the ancestor of all moderns humans or of none.

References here:

[Could DNA testing verify that someone was a time traveler? - #5 by Riemann](https://boards.straightdope.com/t/could-dna-testing-verify-that-someone-was-a-time-traveler/990736/5)

(and subsequent comments in that thread)

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