Lexicon Genetics issued a statement reiterating its claim that Deltagen was continuing to infringe a patent used to produce knockout mice.

Deltagen of Menlo Park, Calif., denied the allegations in an answer filed with the US District Court for the District of Delaware. Deltagen is seeking a grant of declaratory judgment in favor of Deltagen, a biotechnology and genomics company that supplies data to customers such as Merck and Pfizer on the function of mammalian genes.