  The discovery of proto-globular cluster candidates in many current-day
mergers allows us to better understand the possible effects of a merger event
on the globular cluster system of a galaxy, and to foresee the properties of
the end-product. By comparing these expectations to the properties of globular
cluster systems of today's elliptical galaxies we can constrain merger models.
The observational data indicate that i) every gaseous merger induces the
formation of new star clusters, ii) the number of new clusters formed in such a
merger increases with the gas content of the progenitor galaxies.
Low-luminosity (about M_V>-21), disky ellipticals are generally thought to be
the result of a gaseous merger. As such, new globular clusters are expected to
form but have not been detected to date. We investigate various reasons for the
non-detection of sub-populations in low-luminosity ellipticals, i.e. absence of
an old population, absence of a new population, destruction of one of the
populations, and finally, an age-metallicity conspiracy that allows old and new
globular clusters to appear indistinguishable at the present epoch. All of
these possibilities lead us to a similar conclusion, namely that low-luminosity
ellipticals did not form recently (z<1) in a gas-rich merger, and might not
have formed in a major merger of stellar systems at all. High-luminosity
ellipticals do reveal globular cluster sub-populations. However, it is
difficult to account for the two populations in terms of mergers alone, and in
particular, we can rule out scenarios in which the second sub-population is the
product of a recent, gas-poor merger.
