All-Female Amazon Molly Thrives Without Males

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The Amazon molly is an all-female fish species that has reproduced without males for over 100,000 years. It relies on sperm from related species to trigger reproduction but discards the male DNA entirely. A genetic 'copy-and-repair' process helps it avoid the mutation buildup that dooms most asexual species.

Why it matters

The Amazon molly's survival strategy challenges core biological assumptions about the necessity of sexual reproduction for long-term species success. Its unique genome maintenance and adaptation abilities offer insights into human health issues like cancer and genetic disease.

The details

The Amazon molly (Poecilia formosa) traces its origins to a rare 100,000-year-old evolutionary event where a female Atlantic molly and male sailfin molly produced a fertile, all-female hybrid lineage. This provided the species with a diverse genetic foundation that it has preserved through clonal reproduction, discarding male DNA while using sperm to trigger embryo development.

• The Amazon molly lineage originated over 100,000 years ago.
• The species has expanded its range in the Gulf Coast region since the mid-20th century.

What’s next

Researchers continue to study the Amazon molly's unique genome maintenance and adaptation strategies to gain insights into human health issues like cancer and genetic disease.