Message in a bottleneck: Nested founder effects from French Polynesia to Rapa Nui and Hawai'i.

Polynesian populations, especially Hawai'i and Rapa Nui, experienced significantly stronger founder effects than European groups, with two populations showing the most bottlenecked genomes.

• Why it matters: Understanding population-specific genetic variation is crucial for identifying disease risks and developing targeted genetic tests, especially in isolated populations with strong founder effects.
• What they did: Using whole-genome sequencing of Polynesian populations, the study identified two highly bottlenecked groups—Hawai'i and Rapa Nui—and traced their settlement origins to Mangareva, revealing a sequence of oceanic founder events.
• The result: The research uncovered a loss-of-function FAN1 mutation (>1%) common in Eastern Polynesia but absent from gnomAD, highlighting how founder effects generate unique clinical genetic variation in these populations.