  We use the GOODS-MUSIC sample, a catalog of ~3000 Ks-selected galaxies based
on VLT and HST observation of the GOODS-South field with extended
multi-wavelength coverage (from 0.3 to 8 micron) and accurate estimates of the
photometric redshifts to select 179 DRGs with J-Ks>1.3 in an area of 135 sq.
arcmin. We first show that the J-Ks>1.3 criterion selects a rather
heterogeneous sample of galaxies, going from the targeted high-redshift
luminous evolved systems, to a significant fraction of lower redshift (1<z<2)
and less luminous dusty starbursts. These low-redshift DRGs are significantly
less clustered than higher-z DRGs. With the aid of extreme and simplified
theoretical models of clustering evolution we show that it is unlikely that the
two samples are drawn from the same population observed at two different stages
of evolution. High-z DRGs likely represent the progenitors of the more massive
and more luminous galaxies in the local Universe and might mark the regions
that will later evolve into structures of intermediate mass, like groups or
small galaxy clusters. Low-z DRGs, on the other hand, will likely evolve into
slightly less massive field galaxies.
