We propose that dwarf elliptical galaxies are the bound remnants of more massive stellar systems, such as a parent galaxy which has lost more than half its mass in gas ejection during a burst of star formation, or an unbound tidal debris produced during the interaction of two giant galaxies. N-body calculations were performed to study the evolution of stellar systems with postive energy. The results indicate the existence of a power-law relation between the mass and the density sigma of the fragments over a large range of values of sigma, consistent with recent observational evidence. The calculations predict a mass-metallicity relation for the fragments. The amount of unbound material in Virgo Cluster that genetically connected with its dwarf elliptical galaxies is not detectable at present.