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Back on the Ground: Genome Analysis of Convergent Flight Loss in Rails.
Julien Gaspar1,2, Steve A Trewick1, Gillian C Gibb1
1Wildlife & Ecology Group, School of Food Technology and Natural Sciences, Massey University, Private Bag 11-222, Palmerston North, New Zealand.
Journal of Evolutionary Biology
|July 13, 2026
Summary
Flight loss in rails evolved independently through numerous small genetic changes affecting development and regulation, not major mutations. This convergent evolution impacts various biological functions beyond just flight capacity.
Area of Science:
- Evolutionary biology
- Genomics
- Ornithology
Background:
- Convergent evolution leads to similar traits independently.
- Flight loss in rails (Rallidae) is a prime example, with ~25% of species being flightless.
- Island environments often drive flightlessness.
Purpose of the Study:
- Investigate the molecular genetic basis of independent flight loss in rails.
- Identify genes and pathways associated with the loss of flight.
- Understand the evolutionary mechanisms driving convergent flightlessness.
Main Methods:
- Genome-wide comparative analysis of coding regions from seven rail species (4 flightless, 3 volant).
- Utilized over 11,000 alignments and phylogeny-based tests (branch-site models, evolutionary rate analyses).
- Assessed function-altering amino acid substitutions.
Main Results:
- Identified 116 genes significantly associated with flightlessness.
- 37 genes linked to flight capacity (muscle, bone, limb, heart development).
- Genes also related to ecological consequences (immunity, renal function, metabolism, cognition, sensory perception) and gene regulation/modification.
Conclusions:
- Convergent flight loss in rails results from numerous small genetic changes, not major mutations in few genes.
- These changes affect both developmental pathways and regulatory mechanisms.
- Highlights the complex genetic architecture underlying evolutionary adaptations.
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