Joint ownership of data does not limit your ability to incorporate the data into your thesis with permission of the co-owners, and you will own copyright to your thesis as a whole as a result. This does not give you the right to use the data for other purposes without permission if it arose from a joint project. As a general rule, you must obtain permission to use and provide appropriate attribution of the source of data.
Data Are Not Intellectual Property
In legal terms, it is important to remember that data themselves are not intellectual property. They are neither an invention (i.e. patentable) nor an expression of an idea (i.e. a work protected by copyright). Nevertheless, data can be important and a potentially valuable outcome of academic research. If you compile or interpret data in a unique way, you may have an intellectual property interest in the result. The University also has an interest in the resulting intellectual property, if the University has provided resources or facilities that allowed you to compile or interpret the data.
Making Data Public
There are strong scientific conventions that encourage researchers to make data publicly available so others may use them within a reasonable period of time. This promotes the exchange of information between researchers and institutions, allows others to check and challenge results, and helps reduce the overall cost of research. What constitutes a reasonable period of time varies depending on the standards of each research discipline. For example, data collected with SSHRC assistance are public property and must be made accessible to the public normally within two years.