  By reinterpreting the familiar tools and ideas of M-theory model building, we
show how a G2-manifold locally engineered to give rise to massless matter
representations of an SU(5) grand unified model can be smoothly unfolded into a
G2-manifold giving rise to SU(3)xSU(2) gauge theory with the corresponding
matter representations. These ideas could lead to new insights in string
phenomenology because much of the arbitrariness of M-theory model building can
be removed by supposing, for example, that the singularities giving rise to
Standard Model particles could arise from unfolding a more singular, grand
unified geometry.
