Boom-bust population dynamics drive rapid genetic change

Emily J. Stringer, Bernd Gruber, Stephen D. Sarre, Glenda M. Wardle, Scott V. Edwards, Christopher R. Dickman, Aaron C. Greenville, Richard P. Duncan

    Research output: Contribution to journalArticlepeer-review


    Increasing environmental threats and more extreme environmental perturbations place species at risk of population declines, with associated loss of genetic diversity and evolutionary potential. While theory shows that rapid population declines can cause loss of genetic diversity, populations in some environments, like Australia's arid zone, are repeatedly subject to major population fluctuations yet persist and appear able to maintain genetic diversity. Here, we use repeated population sampling over 13 y and genotype-by-sequencing of 1903 individuals to investigate the genetic consequences of repeated population fluctuations in two small mammals in the Australian arid zone. The sandy inland mouse (Pseudomys hermannsburgensis) experiences marked boom-bust population dynamics in response to the highly variable desert environment. We show that heterozygosity levels declined, and population differentiation (FST) increased, during bust periods when populations became small and isolated, but that heterozygosity was rapidly restored during episodic population booms. In contrast, the lesser hairy-footed dunnart (Sminthopsis youngsoni), a desert marsupial that maintains relatively stable population sizes, showed no linear declines in heterozygosity. These results reveal two contrasting ways in which genetic diversity is maintained in highly variable environments. In one species, diversity is conserved through the maintenance of stable population sizes across time. In the other species, diversity is conserved through rapid genetic mixing during population booms that restores heterozygosity lost during population busts.

    Original languageEnglish
    Article numbere2320590121
    Pages (from-to)1-10
    Number of pages10
    JournalProceedings of the National Academy of Sciences of the United States of America
    Issue number18
    Publication statusPublished - Apr 2024


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