The simplicity of filamentous phages makes them an appealing model organism for research in molecular biology, and they have also shown promise as tools in nanotechnology and immunology.

[6][7] However, mining of genomic and metagenomic datasets using a machine learning approach led to the discovery of 10,295 inovirus-like sequences in nearly all bacterial phyla across virtually every ecosystem, indicating that this group of viruses is much more diverse and widespread than originally appreciated.

[8][9] The molecular structure of Ff phages was determined using a number of physical techniques, especially X-ray fiber diffraction,[2][6] solid-state NMR and cryo-electron microscopy.

The fiber diffraction studies identified two structural classes of phage, differing in the details of the arrangement of the gene 8 protein.

[23] Viral assembly occurs at the inner membrane (in case of Gram-negative bacteria), mediated by a membrane-embedded motor protein complex.

[23] This multimeric assembly complex, including p1 encoded by gene 1 (referred to as ZOT, zonula occludens toxin by researchers on Vibrio cholerae phage CTXΦ) is an ATPase containing functional and essential Walker motifs[22] that are thought to mediate the hydrolysis of ATP providing the energy for the assembly of the phage filament.

Since these three phages differ by less than 2 percent in their DNA sequences, corresponding to changes in only a few dozen codons in the whole genome, for many purposes they can be considered to be identical.

[19] Genetic studies on M13 using conditional lethal mutants, initiated by David Pratt and colleagues, led to description of phage gene functions.

This nomenclature persisted for many decades,[9] although the definition of fd as type species was replaced as M13 became more widely used for genetic manipulation,[43][44] and for studies of p8 in membrane mimetic environments.

[46][47][48][49] George Smith and Greg Winter used f1 and fd for their work on phage display for which they were awarded a share of the 2018 Nobel Prize in Chemistry.

The creation and exploitation of many derivatives of M13 for a wide range of purposes, especially in materials science, has been employed by Angela Belcher and colleagues.

[49][50][51][52] Filamentous bacteriophage can promote antibiotic tolerance by forming liquid crystalline domains[53] around bacterial cells.