The short answer is no.
But the department you sre in must have some area of interest? And equipment. What papers does your department publish? You have to have a reseaon for taking this position well let that guide you on what field of science you look into.
Bioscience is a very broad term, are you in cell biology, bioinformatics, cancer markers, disease markers, new drug treatments. Is your university connected to hospital patients, trial studies etc. These all fall under 'bioscience' but not all labs have the facilities for these types of studies or research.
You have to know an area of these, you then narrow the literature, consider what you'd like to see as a career option (such as cancer studies) and see where a gap in knowledge might be that you can try and provide more insight into with your phd.