  We discuss the colour, age and metallicity gradients in a wide sample of
local SDSS early- and late-type galaxies. From the fitting of stellar
population models we find that metallicity is the main driver of colour
gradients and the age in the central regions is a dominant parameter which
rules the scatter in both metallicity and age gradients. We find a consistency
with independent observations and a set of simulations. From the comparison
with simulations and theoretical considerations we are able to depict a general
picture of a formation scenario.
