  We show that for some Hopf subalgebras in U_F(so(M)) nontrivially deformed by
a twist F it is possible to find the nonlinear primitive copies. This enlarges
the possibilities to construct chains of twists. For orthogonal algebra
U(so(M)) we present a method to compose the full chains with carrier space as
large as the Borel subalgebra B(so(M)). These chains can be used to construct
the new deformed Yangians.
