Just to make sure: isn't this an erroneous use of or?
More recently, concerns have been raised that HGT from genetically modified organisms (GMOs) could have adverse effects (Pontiroli et al., 2007). HGT of an introduced gene in a GMO may confer a novel trait in another organism, which could be a source of potential harm to the health of people or the environment. For example, the transfer of antibiotic resistance genes to a pathogen has the potential to compromise human or animal therapy (Bennett et al., 2004), transfer of a viral gene to a non-homologous virus may result in an emerging disease (Falk and Bruening, 1994) or gene transfer to humans has been controversially proposed as a potential trigger for oncogenesis (Ho et al., 2000).
(From "Risks from GMOs due to Horizontal Gene Transfer", by Paul Keese)
P.S. It's hard to formulate why exactly, but it continues to look erroneous to me, although of course I believe J.R. In Russian, such a sentence would be considered erroneous. The minimal solution to make it less wrecked would be to cross out "or" and put "and" in its place. And a comma before "and", of course.