  The evolution of the EMC effect as a function of atomic mass $A$ is
considered for the first time for the lightest nuclei, D, $^3H$, $^3He$ and
$^4He$, with an approach based on the Bethe-Salpeter formalism. We show that
the pattern of the oscillation of the ratio $r^A(x) = F_2^A/F_2^N(D)$ varies
with $A$, unlike the pattern for nuclei with masses $A > 4$, where only the
amplitude of the oscillation changes.
