  We present an alternative interpretation of the observations of BR1202-0725
at z=4.695 and show that its properties are consistent with a relativistic jet,
issuing from the quasar core, propagating into the inter-galactic medium and
triggering star formation along its path. Prompted by this finding, we reviewed
all the z>3 objects detected in molecular line emission and found that the
distribution of gas and dust in these sources is often spatially or
kinematically offset from the host galaxy, and preferentially aligned along the
radio axis. These observations suggest to us a scenario in which CO emission
observed in high redshift galaxies is located where it forms: along the sites
of star formation triggered initially by relativistic jets.
