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Mitochondrial Genome Reduction and Accelerated Evolution in Planktonic Foraminiferans
Hsin-Tung Lai1,2, Ming-Wei Lai1, Tzu-Haw Wang1
1Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.
Microbiologyopen
|July 30, 2026
Summary
Researchers discovered the smallest known mitochondrial genome in planktonic foraminifera. This tiny genome, from a single cell, reveals extreme gene loss and unique evolutionary paths in eukaryotes.
Area of Science:
- Evolutionary Biology
- Genomics
- Microbial Eukaryotes
Background:
- Mitochondrial genomes (mitogenomes) offer insights into eukaryotic evolution.
- Many microbial eukaryotic mitogenomes are underexplored due to cultivation challenges.
- Foraminifera, important marine paleoenvironmental proxies, have poorly studied mitogenomes.
Purpose of the Study:
- To characterize the mitogenome of a planktonic foraminiferan.
- To investigate the extent of genome reduction in Foraminifera.
- To utilize single-cell genomics for microbial genome recovery.
Main Methods:
- Single-cell genomic sequencing was employed.
- A 22-kb mitogenome was recovered from a planktonic foraminiferan.
- Comparative genomic analysis was performed with other Rhizaria.
Main Results:
- The smallest known mitogenome within Rhizaria was identified (22 kb).
- This mitogenome contains only six protein-coding genes and fragmented rRNA genes.
- Extreme gene loss in oxidative phosphorylation and mitochondrial ribosomal proteins was observed.
- Accelerated evolutionary rates and lower GC content were noted compared to benthic foraminifera.
Conclusions:
- This study reveals a unique trajectory of extreme mitogenome reduction in planktonic foraminifera.
- Single-cell genomics is a powerful tool for exploring microbial eukaryotic diversity and evolution.
- Findings expand our understanding of mitochondrial genome evolution in eukaryotes.
Keywords:
ForaminiferaRhizariacomparative genomicsmitogenomeprotistreductive evolutionsingle‐cell genomicsMore Related Videos
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