We study holomorphic families
of compact Riemann surfaces over the punctured unit disk. For every genus p ≥ 3 we
define a family whose relative canonical bundle has no roots of order n > 2. The
monodromy group of that family is generated by a product of powers of
commuting Dehn twists. We give necessary and sufficient conditions for such a
product to generate the monodromy group of a family over the punctured
disk.