A pen name is as significant as an author’s style. Wether you use a pen name or your own name, it will identify you with your genre. Some authors write under different pen names for different genres. A good example of this is Jayne Ann Krentz, who also writes under the pen names of Jayne Castle, and Amanda Quick. Some of her books are: Running Hot (Jayne Ann Krentz), Dark Light (Jayne Castle), and The Perfect Poison (Amanda Quick).
Another good example is Lori Foster or L.L. Foster. Some of her work: Servant The Kindred (L.L. Foster) and Jude’s Law (Lori Foster). In 2007 she launched a new urban fantasy series under the name of L.L. Foster (her darker pen name).
These are good examples of best-selling authors, using different pen names for different genres. Some authors will stick with a genre and a pen name, others will shake things up between genres and pen names.