In The Matrix Reloaded it's revealed that The One is expected to choose 23 individuals (16 females and 7 male) to "rebuild Zion".

This allows the cycle to restart and the Matrix to continue.

However I know that once a species drops below a certain size the gene pool becomes too small and the population's health starts to suffer.

How is it possible, in the films, that 23 unrelated individuals could rebuild Zion or would some kind of genetic engineering be required to eliminate inbreeding?

  • 4
    Maybe the question could be edited to ask about a specific aspect of the hypothetical rebuilding process that would occur in Universe? "Do we have any in universe indication of how these rebuilding cycles deal with genetic diversity when they begin?" Something like that?
    – Harabeck
    Jul 29, 2021 at 16:02
  • 3
    When this gets reopened, the next step is to reclose it as a duplicate of scifi.stackexchange.com/questions/32198/…
    – Valorum
    Jul 29, 2021 at 19:44
  • @Valorum it looks like that question is about the ratio not the number. Oddly that's not how it was answered
    – AncientSwordRage
    Jul 29, 2021 at 20:36
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  • It still feels firmly dupey to me
    – Valorum
    Jul 29, 2021 at 21:09

1 Answer 1


You're correct, that twenty-three individuals can't carry enough genetic diversity for long term population growth, but in this case, they don't need to. Don't forget that those who found each Zion will gain access to additional genes as they free others from the Matrix.

The number is probably symbolic in some fashion (one for each chromosome pair in a human cell?), but mainly it's enough people to sustain themselves while stealing/rebuilding/recovering enough technology from the machines to begin reentering the Matrix -- which is a prerequisite to begin to free additional red-pills, each of which will (presumably, at least in most cases) contribute to the diversity of the next generation.

  • I don't know why this was downvoted -- it is correct.
    – Null
    Jul 29, 2021 at 15:51
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    @Null Some folks automatically downvote any answers on a question they vote to close, or one that actually gets closed. I've done it myself -- "don't answer questions that should be closed." When I wrote this answer, that wasn't completely clear, however.
    – Zeiss Ikon
    Jul 29, 2021 at 15:56
  • Unless the answer is edited to be about Zion alone, this doesn't actually answer the question. Pedantic perhaps, but it would be good to be certain what the OP is after assuming they want to make it on topic.
    – AncientSwordRage
    Jul 29, 2021 at 15:59
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    FWIW, the figure isn't agreed upon, but the minimum viable population - assuming genetic pre-screening, mandatory breeding, large families and strict rules on mixing - is at least 80.
    – DavidW
    Jul 29, 2021 at 16:00
  • Use of "the civilisation" implies that this does refer to Zion specifically -- if it were just "civilisation" it would be general.
    – Zeiss Ikon
    Jul 29, 2021 at 16:00

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