Starting from the microscopic low-momentum nucleon-nucleon interaction V low k , we present the first systematic shell model study of magnetic moments and magnetic dipole transition strengths of the basic low-energy one-quadrupole phonon excitations in nearly-spherical nuclei. Studying in particular the even-even N = 52 isotones from 92 Zr to 100 Cd , we find the predicted evolution of the predominantly proton-neutron non-symmetric state reveals a restoration of collective proton-neutron mixed-symmetry structure near mid-shell. This provides the first explanation for the existence of pronounced collective mixed-symmetry structures in weakly-collective nuclei.PACS numbers: 21.60. Cs, Mesoscopic quantum systems such as Bose-Einstein condensates, superconductors, and quark-gluon systems are some of the most intensely studied in contemporary physics [1,2]. Their dynamical properties are determined by the interplay and mutual balance of collective and single-particle degrees of freedom. In two fluid systems such as atomic nuclei, the presence of an isospin degree of freedom only serves to enhance this complexity. Of particular interest for understanding the physics of these systems is the microscopic origin of those excitations possessing collective two-fluid character. Collective quadrupole isovector excitations in the valence shell, socalled mixed-symmetry states (MSSs) [3], are the beststudied examples of this class of excitations. A special type of MSS, the 1 + scissor mode, was predicted to exist [4] and discovered [5] in atomic nuclei. It is not surprising then, that analogous scissor-mode states have subsequently been found in other two-fluid quantum systems such as trapped Bose-Einstein condensed gases [6,7], metallic clusters [8], and elliptical quantum dots [9].Even though MSSs are a common feature of two-fluid quantum systems, atomic nuclei are still the primary laboratory in which our understanding of them can be shaped. In the interacting boson model of heavy nuclei (IBM-2) the definition of MSSs is formalized by the bosonic F -spin symmetry [3]. It arises predominantly from a collective coupling of proton and neutron sub-systems, and when the proton/neutron (pn) valence spaces are large enough, strong coupling can arise between them. Naturally then, the best examples of pnsymmetric and MSSs would be expected at mid shells. However, pronounced MSSs have recently also been observed in weakly collective nuclei especially in N = 52 isotones. Multiphonon structures of MSSs are observed in the nucleus 94 Mo [10,11,12], in neighboring nuclei * Electronic address: jholt@triumf.ca [13,14,15], and recently the first MSSs in an oddmass nearly-spherical nucleus were identified in 93 Nb [16]. Even though the experimental properties of MSSs in this region have been well described within the framework of the IBM-2 [17,18], the nuclear shell model (SM) [14,19], and the quasiparticle-phonon model [20], the question of how these states arise and evolve has not yet been answered.In this Letter, we provide the first micros...