Gene sequencing firm Pacific Biosciences is suing rival Oxford Nanopore Technologies for patent infringement, after successfully filing a broad patent on nanopore sequencing technology.

PacBio claims that Oxford Nanopore’s MinIon and PromethIon sequencers – which use protein-based pores to electronically read nucleic acid sequences – infringe US patent 9546400, granted to PacBio in January 2017. PacBio’s own sequencers employ its Single Molecule Real Time (SMRT) sequencing technology, in which sequences are determined by synthesising complementary DNA strands inside nanosized ‘waveguide’ wells.

‘We believe this is another frivolous lawsuit brought by a competitor nervous about our superior technology,’ said Oxford Nanopore’s chief executive, Gordon Sanghera in a statement. The company was sued for patent infringement by sequencing heavyweight Illumina in 2016, but settled the dispute by switching to a different pore protein.