  Dark matter, baryonic matter and dark energy have different properties but
contribute comparable energy density to the present Universe. We point out that
they may have a common origin. As the dark energy has a scale far lower than
all known scales in particle physics but very close to neutrino masses, while
the excess matter over antimatter in the baryonic sector is probably related to
the neutrino mass-generation, we unify the origin of dark and visible Universe
in a variant of seesaw model. In our model (i) the dark matter relic density is
a dark matter asymmetry emerged simultaneously with the baryon asymmetry from
leptogenesis; (ii) the dark energy is due to a pseudo-Nambu-Goldstone-Boson
associated with the neutrino mass-generation.
