The last bacterial common ancestor encoded the components of a functionally complete flagellum

The last bacterial common ancestor encoded a functionally complete flagellum, with 50 ancestral protein groups reconstructed from 80,789 bacterial proteomes.

• Why it matters: Prior work inferred only 24 ancestral flagellar genes, leaving uncertainty whether LBCA had a simpler system or whether divergence hid additional ancestral components.
• What they did: The authors combined large-scale homology searches, conserved sequence signatures, gene-tree clustering, and gene-neighborhood evidence across 80,789 proteomes to infer ancestral presence.
• The result: They found 49 high-confidence ancestral flagellar protein groups plus one likely component, enabling a reconstructed repertoire that implies extensive later lineage-specific loss and remodeling.

AI summary of the abstract · may contain errors · not medical advice · read the paper.