Nature Podcast

This fish shouldn’t exist — the weird genetics of clonal vertebrates

6 snips
Mar 11, 2026
A deep dive into the bizarre genetics of an all-female, clonal fish that should have gone extinct. Scientists reveal how gene conversion may erase harmful mutations and keep the lineage alive. The show then shifts to ultra-bright supernovae with rhythmic, chirping light curves. Researchers explore magnetars and tilted accretion disks as explanations and anticipate future sky surveys.
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INSIGHT

Amazon Molly Defies Mutation Accumulation Predictions

  • The Amazon molly is an all-female clonal fish that arose ~100,000 years ago yet should have gone extinct under mutation-accumulation theory.
  • Edward Reissmeyer and colleagues compared its genome to both sexual parent species and found faster mutation accumulation but not more deleterious variants, challenging expectations.
INSIGHT

Gene Conversion Acts As Genome Repair In Clonal Fish

  • Gene conversion repairs damaged DNA by copying from the homologous chromosome, acting like a copy-and-paste repair between genome copies.
  • The team showed gene conversion actively removes harmful mutations in the Amazon molly, helping maintain its clonal genome over long timescales.
INSIGHT

Gynogenesis Links Clonal Reproduction To Other Species

  • Amazon mollies require sperm from related species to trigger egg development (gynogenesis) but do not use paternal DNA for fertilisation.
  • This unique life cycle means the species depends on coexisting sexual species even while reproducing clonally.
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