What's The Fewest People That Could Repopulate Earth?

If nuclear blasts, asteroids, or alien lasers killed off almost all humans on Earth, how many people would be needed to rebuild a genetically sustainable human population? LEARN MORE ************** To learn more about this topic, start your googling with these keywords: Gene Pool: The total collection of different genes within a population. A larger gene pool means more genetic diversity. Genetic Diversity: Having a wide variety of different genes within a population. Inbreeding Depression: The reduced biological fitness caused by loss of genetic diversity as a result of inbreeding, or mating between closely related individuals within a species. Recessive Genes: Genes that only cause a trait or disease when two copies are present (one from each parent). SUPPORT MINUTEEARTH ************************** If you like what we do, you can help us!: Become our patron:   / minuteearth   Our merch: store.dftba.com/me Our book: https://minuteearth.com/books Sign up to our newsletter: http://news.minuteearth.com Share this video with your friends and family Leave us a comment (we read them!) CREDITS ********* Cameron Duke | Script Writer, Narrator and Director Arcadi Garcia i Rius | Storyboard Artist Sarah Berman | Illustration, Video Editing and Animation Nathaniel Schroeder | Music MinuteEarth is produced by Neptune Studios LLC https://neptunestudios.info OUR STAFF ************ Lizah van der Aart • Sarah Berman • Cameron Duke Arcadi Garcia i Rius • David Goldenberg • Melissa Hayes Henry Reich • Ever Salazar • Leonardo Souza • Kate Yoshida OUR LINKS ************ Youtube |    / minuteearth   TikTok |   / minuteearth   Twitter |   / minuteearth   Instagram |   / minute_earth   Facebook |   / minuteearth   Website | https://minuteearth.com Apple Podcasts| https://podcasts.apple.com/us/podcast... REFERENCES ************** Chaudhary, V., & Oli, M. K. (2020). A critical appraisal of population viability analysis. Conservation Biology, 34(1), 26–40. https://doi.org/10.1111/cobi.13414 Gutiérrez, D. (2002). The importance of unprotected habitats for the persistence of a metapopulation of the dingy skipper butterfly (Erynnis tages) in a fragmented landscape. Conservation Biology, 16(3). https://doi.org/10.1046/j.1523-1739.2... Hu, W., Hao, Z., Du, P., Di Vincenzo, F., Manzi, G., Cui, J., Fu, Y.-X., Pan, Y.-H., & Li, H. (2023). Genomic inference of a severe human bottleneck during the Early to Middle Pleistocene transition. Science, 381(6661), 979–984. https://doi.org/10.1126/science.abq7487 Marin, F., & Beluffi, C. (2018). Computing the minimal crew for a multi-generational space journey towards Proxima Centauri b. Journal of the British Interplanetary Society, 71(2), 430–437. Mills, L. S. (2013). Conservation of wildlife populations: Demography, genetics, and management (2nd ed.). Wiley-Blackwell. Rai, U. K. (2003). Minimum sizes for viable population and conservation biology. Our Nature, 1(1), 3–9. https://doi.org/10.3126/on.v1i1.297 Reed, D. H., O'Grady, J. J., Brook, B. W., Ballou, J. D., & Frankham, R. (2003). Estimates of minimum viable population sizes for vertebrates and factors influencing those estimates. Biological Conservation, 113(1), 23–34. https://doi.org/10.1016/S0006-3207(02... Sano, S. (2022). Cultural evolution and minimal crew size to maintain culture level during interstellar travel. Journal of the British Interplanetary Society, 75(4), 118–126. Sano, S. (2023). Minimal crew size and sensitive reproductive parameters on multigenerational interstellar travel. Journal of the British Interplanetary Society, 76(8), 288–296. https://doi.org/10.59332/jbis-076-08-... Schiffels, S., & Durbin, R. (2014). Inferring human population size and separation history from multiple genome sequences. Nature Genetics, 46(8), 919–925. https://doi.org/10.1038/ng.3015 Smith, C. M. (2014). Estimation of a genetically viable population for multigenerational interstellar voyaging: Review and data for project Hyperion. Acta Astronautica, 97, 16–29. https://doi.org/10.1016/j.actaastro.2... Traill, L. W., Brook, B. W., Frankham, R. R., & Bradshaw, C. J. A. (2010). Pragmatic population viability targets in a rapidly changing world. Biological Conservation, 143(1), 28–34. https://doi.org/10.1016/j.biocon.2009... Waples, R. S. (2025). The idiot's guide to effective population size. Molecular Ecology. https://doi.org/10.1111/mec.17670 Yampolskiy, R. V. (2018). Minimum viable human population with intelligent interventions [Unpublished manuscript]. University of Louisville.