  We discuss various aspects of the early petite unification (PUT) of quarks
and leptons based on the gauge group G_PUT=SU(4)_PS x SU(2)_L x SU(2)_R x
SU(2)_H. This unification takes place at the scale M= O(1-2 TeV) and gives the
correct value of sin^2 theta_W(M_Z^2) without the violation of the upper bound
on the K_L -> mu e rate and the limits on FCNC processes. These properties
require the existence of three new generations of unconventional quarks and
leptons with charges up to 4/3 (for quarks) and 2 (for leptons) and masses
O(250 GeV) in addition to the standard three generations of quarks and leptons.
The horizontal group SU(2)_H connects the standard fermions with the
unconventional ones. We work out the spontaneous symmetry breaking (SSB) of the
gauge group G_PUT down to the SM gauge group, generalize the existing one-loop
renormalization group (RG) analysis to the two-loop level including the
contributions of Higgs scalars and Yukawa couplings, and demonstrate that the
presence of three new generations of heavy unconventional quarks and leptons
with masses O(250 GeV) is consistent with astrophysical constraints. The NLO
and Higgs contributions to the RG analysis are significant while the Yukawa
contributions can be neglected.
