Crystallographic slip at the beginning stages of plastic deformation is investigated via an atomistic (molecular statics) model. Attention is devoted to face-center-cubic metallic crystals in the form of a nanowire under uniaxial tensile loading. The simulation parameters employed in this work are such that dislocation slip behavior can be observed without the influence of surface stress and phase transformation. The incorporation of an initial embedded point defect in the model causes plastic deformation to be facilitated in a controlled manner. Two crystallographic orientations are studied, and , which result in, respectively, single slip and double slip at the onset of plastic yielding. Detailed mechanisms of dislocation evolution and their glide features are analyzed.