Wall lizards introduced to Cincinnati, Ohio, have flourished despite a severe genetic bottleneck, new research reveals. The non-native reptiles expanded their population so quickly that harmful genes amplified by inbreeding failed to undermine their survival.
The findings challenge conventional understanding of how small, isolated populations persist. Typically, inbreeding concentrates deleterious mutations, increasing extinction risk. These lizards, however, outpaced that threat through sheer reproductive speed.
Scientists sequenced the genomes of multiple individuals, uncovering signs of a pronounced bottleneck followed by explosive growth. The rapid expansion effectively diluted the impact of harmful alleles that would otherwise accumulate in a stagnant population.
The study suggests that population growth rate can be a critical factor in species resilience. Conservation efforts for endangered species may need to prioritize not just genetic diversity but also conditions that enable swift population increases.
Experts caution that this strategy may not work for all species, particularly those with slower reproduction. The findings offer a new lens on evolutionary rescue but underscore that context matters significantly.