“…For example, most forkhead factors (e.g., Foxa2 and Foxo3) can bind both a primary forkhead motif (RYAAAYA) and a secondary motif (AHAACA) (R = A or G, Y = C or T, H = A, C, or T) (Badis et al, 2009;Mariani, Weinand, Vedenko, Barrera, & Bulyk, 2017). While the overall prevalence of this phenomenon among TFs is debated, it is clear that for some TF classes, such diversity in the types of DNA sequences they can recognize is genuine (Morris, Bulyk, & Hughes, 2011;Siggers et al, 2012;Zhao & Stormo, 2011).…”