A patent at the centre of a heated court battle over tools used for research into Alzheimer's disease (see above) itself emerged from a controversial arrangement between an expatriate British scientist and a public university in Florida. In addition, a Swedish research team argues that it should have shared in the rights.

The patent covers the genetic sequence of a human mutation that causes Alzheimer's disease and its use in transgenic mice (Nature Genet. 1, 345–347; 1992). It was invented by Michael Mullan, a neuroscientist who trained at Imperial College in London.

Mullan says he received the rights to the discovery under a deal with the University of South Florida in Tampa.

Mullan left England in 1992 and moved to the university having, he says, become disheartened with how he was treated when Imperial College sought to capitalize on his scientific discoveries.

Mullan says his terms of employment at South Florida allowed him to own the patents on any scientific discoveries he made within about six months of his arrival in Florida.

During this time Mullan and his colleagues sequenced the gene in question. Mullan sold the patent rights to the Alzheimer's Institute of America, a company set up by Kansas venture capitalist Ron Sexton, who had been funding Mullan's work. The Mayo Foundation later licensed the technology from Sexton's firm.

Kenneth Preston, the University of South Florida's director of patents and licensing, acknowledges that initially “there was an agreement not to apply rules and procedures regarding intellectual property” to Mullan. He also accepts that, as a result, a discovery that would normally have been owned by the university ended up in private hands.

Mullan, who now directs the university's Roskamp Institute, says that he did everything “above board” and “in full view of everyone”. He says that the university's officials “felt sympathetic” to him for having been badly treated by Imperial College. The college declines to comment on the issue.

In 1991, Imperial College sold the rights to the first Alzheimer's mutation that Mullan helped to discover (see Nature 353, 844–846; 1991) to Athena Neurosciences, Inc., which was later bought by Elan, the company at the heart of last week's court hearing.

Another twist is the fact that the DNA used by Mullan to sequence the mutation at South Florida was provided by a Swedish research team headed by Bengt Winblad, chief of clinical neuroscience at the Karolinska Institute in Stockholm.

In publishing the findings, Mullan shared co-authorship with the Swedes in the 1992 Nature Genetics article. But he listed himself as sole inventor on the US patent, which was granted in 1995.

Lars Lannfelt, a neurogenetics professor on Winblad's team who unsuccessfully fought for recognition on the patent, claims that he and his colleagues should not have been omitted. Mullan denies this, arguing that the Swedish researchers “didn't have a position” as inventors, because they only provided DNA, and made no intellectual contribution.