Genetic Study Reveals How Inbreeding and Lethal Mutations Drive High Mortality in Endangered Devils Hole Pupfish
A new genomic study of the critically endangered Devils Hole pupfish found that inbreeding and a recessive lethal haplotype cause up to 25% of embryonic deaths in captive populations. The research identified specific genetic mutations in genes linked to heart disease that account for about half of these deaths. The findings illustrate how small, isolated populations accumulate genetic damage over thousands of generations, threatening species survival even when diversity is already extremely low.
Researchers analyzing the Devils Hole pupfish, one of the world's rarest fish species, discovered that the population's extreme genetic isolation has created compounding threats to survival. Using comparative genomics, historical DNA sequencing, and embryo sampling, the team found that genetic diversity in the species is among the lowest ever recorded in wild populations, with high genetic load accumulated over thousands of generations at small population size. Despite this already-depleted diversity, inbreeding continues to cause significant harm: up to 25% of offspring in captive refuges die prematurely during development, identifiable by an elongated heart tube and reduced heart rate. A single recessive lethal haplotype segregating at approximately 20% frequency accounts for roughly half of these embryonic deaths and contains mutations in MIB1 and MMP16, genes associated with cardiomyopathy and atrial fibrillation. The study provides a rare comprehensive view of how long-term small effective population size shapes evolutionary dynamics and demonstrates that endangered species remain vulnerable to inbreeding depression even when genetic diversity is already critically low.
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- bioRxivCenter
Long-term small effective population size, inbreeding, and a recessive lethal haplotype drive premature death in the endangered Devils Hole pupfish (Cyprinodon diabolis)
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