Before starting work on how the user will interact with your tool, it is important to see what else is out there. This will help you see see what useful conventions you can follow as well as inspire areas where you can improve upon current designs. This is good to do whether starting from scratch or refining/revising a current interface.
Tools that do as close to what you are doing as possible
Tools in your field in general
Tools outside of genomics/biology/etc that conceptually do something similar, such as searching, mapping, editing, etc.
The first group will help you brainstorm ideas from what other people have done, and also see what improvements you can make on competitors in the field.
The second will help you understand general paradigms and conventions in the field (e.g. introns being represented as lines and exons as boxes). It is important to mimic these norms as much as possible, unless there is a strong reason to do otherwise.
The final group will help you think outside the box and find novel ways of guiding users and presenting information.
If your tool is truly unique it is even more important to mimic as much as possible any other tool that might be even slightly related. A design should try to reduce the gap between what the user is used to and the new technology.