Illumina and BGI are due for a showdown in a German Court in the near future. San Diego-based Illumina said it has filed a patent infringement suit against one of BGI Group’s subsidiaries Latvia MGI Tech SIA.

The lawsuit alleges that Shenzhen, China-based BGI’s sequencing products, including the BGISeq-500, MGISeq-2000, and related chemistry reagents, infringe EP 1 530 578 B1. This patent covers Illumina’s sequencing-by-synthesis chemistry.

“Illumina will not tolerate the unauthorized, infringing use of its patented technology. Illumina filed this suit to defend the substantial investments we have made in our industry leading sequencing technology, as validated in our global intellectual property portfolio,” Charles Dadswell, Senior vice president and general counsel for Illumina, said in a release. “We will continue to monitor the field and file patent suits where appropriate when our patents are infringed.

The ‘578 patent is one of numerous patents that protect Illumina’s sequencing technology. Its validity has been affirmed by the European Patent Office in opposition proceedings.

Similarly, the U.S. counterpart to the ‘578 patent was upheld by the U.S. Patent Trial and Appeal Board over challenges filed by BGI and its subsidiary, Complete Genomics, Inc., in Inter PartesReview Nos. IPR2017-02172 and IPR2017-02174.

The lawsuit comes on the heels of Illumina making a proposal to acquire PacificBio for $1.2 billion. PacBio fills an important gap in Illumina’s offerings.

For years Illumina has prided itself on using short-read technology to sequence DNA. This means it takes lots of small fragments of DNA and puts them together. However, PacBio is the opposite and has long-read sequencing capabilities, which means it can decode longer pieces of DNA with high accuracy. The deal is set to close in mid-2019.