In Regents of the University of Minnesota v. Gilead, the Federal Circuit determined that UMN’s claim of priority to a provisional application for their ’830 patent lacked sufficient written description. The court made this determination by analyzing whether there was ipsis verbis support and whether there were sufficient blaze marks in the original application to guide the skilled artisan to the ’830 application. First, the court determined that UMN’s piece-meal analysis of the priority application to show ipsis verbis support of the later claimed subgenus did not meet the ipsis verbis standard. Second, it also found that the priority application lacked the blaze marks to guide a skilled artisan. It made this determination by finding that the structures in this case were so extensive and varied, through its multiple dependencies that encompassed a significantly large genus, such that there was no sufficient commonality to provide written description support for the subgenus found in the ’830 patent.