# Dave Chang: Migration Paths for a Genealogical Ancestor?

**URL:** <https://discourse.peacefulscience.org/t/dave-chang-migration-paths-for-a-genealogical-ancestor/9985>\
**Category:** Side Conversation\
**Tags:** Science\
**Created:** [March 22, 2020, 9:07pm UTC](https://discourse.peacefulscience.org/t/dave-chang-migration-paths-for-a-genealogical-ancestor/9985 "2020-03-22T21:07:37Z")\
**Posts on this page:** 10\
**Page:** 1

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**Author:** ![Dave\_Chang](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/dave_chang/32/7671_2.png) [@Dave\_Chang](https://discourse.peacefulscience.org/u/Dave_Chang)\
**Post date:** [March 22, 2020, 9:07pm UTC](https://discourse.peacefulscience.org/t/dave-chang-migration-paths-for-a-genealogical-ancestor/9985/1 "2020-03-22T21:07:37Z")

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Hello everyone! Would really appreciate any help to my questions on how Adam/Eve (created de novo ~ 10000 years ago in the Middle East) could be genealogical ancestors of everyone alive by 1 AD.

Based on our current understanding, the first humans left Africa ~ 60,000 years ago, arrive in Australia ~ 50,000 years ago and the Americas ~ 35,000 years ago. Suppose that Adam/Eve existed 10,000 years ago, has any scientist commented about the plausibility that their descendants could plausibly follow the same migration paths and interbreed with humans that already live in these remote parts of the world?

Would you say that a potential challenge for the genealogical hypothesis to work is to have a conceivable framework to show that it’s possible for Adam/Eve’s descendants to actually repeat those migration paths from ~ 8,000 BC to 1 A.D.?

Appreciate any insight/feedback here

Warm regards  
Dave

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**Author:** ![John\_Harshman](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/john_harshman/32/1121_2.png) [@John\_Harshman](https://discourse.peacefulscience.org/u/John_Harshman)\
**Post date:** [March 23, 2020, 12:19am UTC](https://discourse.peacefulscience.org/t/dave-chang-migration-paths-for-a-genealogical-ancestor/9985/2 "2020-03-23T00:19:08Z")

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There has been regular contact across the Bering Strait for quite a long time, including at least three major migrations from Asia (Amerindian, Na-Dene, Inuit). Similarly, there has been contact across the Torres Strait for a long time too. The only major problem is Tasmania. You should ask @swamidass about his geographical model. (Perhaps a graphic representation would be good here.)

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**Author:** ![swamidass](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/swamidass/32/3_2.png) [@swamidass](https://discourse.peacefulscience.org/u/swamidass)\
**Post date:** [March 23, 2020, 1:54am UTC](https://discourse.peacefulscience.org/t/dave-chang-migration-paths-for-a-genealogical-ancestor/9985/3 "2020-03-23T01:54:50Z")

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Hello @Dave_Chang. Nice to meet you.

As @John_Harshman notes, let’s leave aside Tasmania for a moment.

> [@Dave\_Chang](#):
>
> Based on our current understanding, the first humans left Africa ~ 60,000 years ago, arrive in Australia ~ 50,000 years ago and the Americas ~ 35,000 years ago. Suppose that Adam/Eve existed 10,000 years ago, has any scientist commented about the plausibility that their descendants could plausibly follow the same migration paths and interbreed with humans that already live in these remote parts of the world?

Yes, many have. None of these places (except maybe Tasmania) were totally isolated over the last 10,000 years. The fact that some people, for example, crossed to Australia 60,000 years ago does not mean that more did not follow later. In many cases we have evidence that they did.

Have you had a chance to read the book yet?

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**Author:** ![John\_Harshman](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/john_harshman/32/1121_2.png) [@John\_Harshman](https://discourse.peacefulscience.org/u/John_Harshman)\
**Post date:** [March 23, 2020, 3:54am UTC](https://discourse.peacefulscience.org/t/dave-chang-migration-paths-for-a-genealogical-ancestor/9985/4 "2020-03-23T03:54:41Z")

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Any chance for that graphic representation of your model of geographic structure?

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**Author:** ![swamidass](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/swamidass/32/3_2.png) [@swamidass](https://discourse.peacefulscience.org/u/swamidass)\
**Post date:** [March 23, 2020, 5:52am UTC](https://discourse.peacefulscience.org/t/dave-chang-migration-paths-for-a-genealogical-ancestor/9985/5 "2020-03-23T05:52:06Z")

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It is in the 2004 Rohdes paper.

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**Author:** ![Dave\_Chang](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/dave_chang/32/7671_2.png) [@Dave\_Chang](https://discourse.peacefulscience.org/u/Dave_Chang)\
**Post date:** [March 23, 2020, 1:04pm UTC](https://discourse.peacefulscience.org/t/dave-chang-migration-paths-for-a-genealogical-ancestor/9985/6 "2020-03-23T13:04:30Z")

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Thanks much for the replies, guys! OK I have found my way to some earlier threads at the Biologos forum and this forum on Tasmania’s isolation. Interesting debate there…

Would you kindly point me to any resources or articles on evolutionary anthropology that explain how these migrations occurred in the last 10K years? Curious to learn more.

On the Rohde 2004 paper… assume it’s this one?

> <https://www.ncbi.nlm.nih.gov/pubmed/15457259>
>
> If a common ancestor of all living humans is defined as an individual who is a genealogical ancestor of all present-day people, the most recent common ancestor (MRCA) for a randomly mating population would have lived in the very recent past. However, the random mating model ignores essential aspects of population substructure, such as the tendency of individuals to choose mates from the same social group, and the relative isolation of geographically separated groups. Here we show that recent common ancestors also emerge from two models incorporating substantial population substructure. One model, designed for simplicity and theoretical insight, yields explicit mathematical results through a probabilistic analysis. A more elaborate second model, designed to capture historical population dynamics in a more realistic way, is analysed computationally through Monte Carlo simulations. These analyses suggest that the genealogies of all living humans overlap in remarkable ways in the recent past. In particular, the MRCA of all present-day humans lived just a few thousand years ago in these models. Moreover, among all individuals living more than just a few thousand years earlier than the MRCA, each present-day human has exactly the same set of genealogical ancestors.

From the blurb, it seems that the mathematical model ignores _isolation of geographically separated groups_. Wouldn’t that have a negative impact on GAE hypothesis?

Sorry I haven’t read the book yet.

Heard about it from Unbelievable podcast/Christianity Today, and my first knee jerk reaction is to wonder about the plausibility (not just possibility) of their descendants reaching those far-reaching places in a few thousand years…

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**Author:** ![John\_Harshman](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/john_harshman/32/1121_2.png) [@John\_Harshman](https://discourse.peacefulscience.org/u/John_Harshman)\
**Post date:** [March 23, 2020, 1:35pm UTC](https://discourse.peacefulscience.org/t/dave-chang-migration-paths-for-a-genealogical-ancestor/9985/7 "2020-03-23T13:35:23Z")

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> [@Dave\_Chang](#):
>
> it seems that the mathematical model ignores _isolation of geographically separated groups_ .

No, it explicitly incorporates that structure. That’s the second model “designed to capture historical population dynamics in a more realistic way”. Note that they’re talking not about complete isolation but about “relative isolation”. There are no human populations that have been completely isolated for thousands of years, with the probable exception of Tasmania.

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**Author:** ![swamidass](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/swamidass/32/3_2.png) [@swamidass](https://discourse.peacefulscience.org/u/swamidass)\
**Post date:** [March 23, 2020, 2:14pm UTC](https://discourse.peacefulscience.org/t/dave-chang-migration-paths-for-a-genealogical-ancestor/9985/8 "2020-03-23T14:14:47Z")

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The “debate” at BioLogos did not include me and will mislead you on material facts regarding Tasmania. Here is how Tasmania impacts the analysis:

> **[How does the isolation of Tasmania impact recent universal ancestry?](https://peacefulscience.org/isolation-tasmania/)**
>
> The question of Tasmania pulls us deeper into science, wondering together about what we know and the limits of our knowledge. Let the conversation grow.

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**Author:** ![John\_Harshman](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/john_harshman/32/1121_2.png) [@John\_Harshman](https://discourse.peacefulscience.org/u/John_Harshman)\
**Post date:** [March 23, 2020, 3:14pm UTC](https://discourse.peacefulscience.org/t/dave-chang-migration-paths-for-a-genealogical-ancestor/9985/9 "2020-03-23T15:14:53Z")

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> [@swamidass](#):
>
> It is in the 2004 Rohdes paper.

Paywalled.

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**Author:** ![swamidass](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/swamidass/32/3_2.png) [@swamidass](https://discourse.peacefulscience.org/u/swamidass)\
**Post date:** [March 23, 2020, 8:01pm UTC](https://discourse.peacefulscience.org/t/dave-chang-migration-paths-for-a-genealogical-ancestor/9985/10 "2020-03-23T20:01:18Z")

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@Dave_Chang, [Three Reviews at BioLogos](https://discourse.peacefulscience.org/t/three-reviews-at-biologos/9994) just came up and you might want to see them. Peace.