  By means of detailed chemical evolution models for galaxies of different
morphological types (i.e. spirals, irregular/starburst galaxies and
ellipticals) we study the nature of Damped Lyman-Alpha systems. Our concern is
to infer which systems represent likely candidates for the DLA population and
which do not. By focusing on individual systems, we can derive some constraints
on both the nature of the associated galaxy and its age. Our results indicate
that, owing to their high metallicities and [alpha/Fe] ratios, big spheroids
represent unlikely DLA candidates whereas spirals (observed at different
galactocentric distances) and irregulars are ideal sites where DLA absorptions
can occur.
