We address two interrelated problems concerning permutation of roots of univariate polynomials whose coefficients depend on parameters. First, we compute the Galois group of polynomials ϕ) is generic with respect to its support set A ⊂ Z k+1 , we determine the latter Galois group for any A. Second, we determine the Galois group of systems of polynomial equations of the form p(x, t) = q(t) = 0 where p and q have prescribed support sets A 1 ⊂ Z 2 and A 2 ⊂ {0} × Z respectively. For each problem, we determine the image of an appropriate braid monodromy map in order to compute the sought Galois group. Among other topics, the present results apply to the computation of the Galois group of some general enumerative problems, to Zariski's theorem on the fundamental group of the complement to projective hypersurfaces and to the determination of the kernel as well as the isomonodromy loci of the braid monodromy maps involved.