  We present a new correlation between the mass-to-light (M/L) ratio and the
mean metallicity for the satellites of the Local Group. This relation together
with their central surface brightness define a Fundamental Line where metal
poor and low surface brightness dwarfs are dark matter dominated while metal
rich high surface brightness systems will have a low M/L ratio. This
Fundamental Line is independent of distance to the central galaxy (M31 and the
Milky Way) and morphological type among other global parameters as their star
formation history. The new M/L-metallicity relation indicates that dwarf
spheroidal galaxies are dark matter confined. It can be interpreted if
satellites experienced a continuous loss of metals with a final episode of gas
ejection at the end of the star formation epoch. Only Globular Clusters are
found to lie outside the Fundamental Line of dwarf satellites. Unlike satellite
galaxies they are not dark matter confined.
