  In a theory with broken supersymmetry, gaugino couplings renormalize
differently from gauge couplings, as do higgsino couplings from Higgs boson
couplings. As a result, we expect the gauge (Higgs boson) couplings and the
corresponding gaugino (higgsino) couplings to evolve to different values under
renormalization group evolution. We re-examine the renormalization group
equations (RGEs) for these couplings in the Minimal Supersymmetric Standard
Model (MSSM). To include threshold effects, we calculate the $\beta$-functions
using a sequence of (non-supersymmetric) effective theories with heavy
particles decoupled at the scale of their mass. We find that the difference
between the SM couplings and their SUSY cousins that is ignored in the
literature may be larger than two-loop effects which are included, and further
that renormalization group evolution induces a non-trivial flavour structure in
gaugino interactions. We present here the coupled set of RGEs for these
dimensionless gauge and "Yukawa"-type couplings. The RGEs for the dimensionful
SSB parameters of the MSSM will be presented in a companion paper.
