There is a proliferation of research and industrial organizations that produce sources of huge amounts of biological data issuing from experimentation with biological systems. In order to make these heterogeneous data sources easy to use, several efforts at data integration are currently being undertaken based mainly on XML. Starting from a discussion of the main biological data types and system
... [Show full abstract] interactions that need to be represented, the authors deal with the main approaches proposed for their modelling through XML. Then, they show the current efforts in biological data integration and how an increasing amount of Semantic information is required in terms of vocabulary control and ontologies. Finally, future research directions in biological data integration are discussed.