Trends in the energy staggering of the \pi h_11/2\nu i_13/2 and \pi h_11/2\nu h_11/2 bands in the mass 160 and 130 regions, respectively, have been investigated in order to better understand the origin of signature inversion. While the A\approx 160 nuclei behave in a consistent manner, a more complicated scenario is observed in the mass 130 region. As a result of our experiments on the lightest Pr nuclei, the systematics of these Z=59 nuclei have been extended, which aids in the understanding of the latter region. Triaxial deformation, a pn interaction, and quadrupole pairing are considered as possible contributors to this effect. As all the chiral-twin bands that are known have signature inversion in the favored band, a possible link between the two phenomena should be considered.

PACS numbers: 21.10.Re, 23.20.Lv, 27.60.+j