  The Yakushevich model of DNA torsion dynamics supports soliton solutions,
which are supposed to be of special interest for DNA transcription. In the
discussion of the model, one usually adopts the approximation $\ell_0 \to 0$,
where $\ell_0$ is a parameter related to the equilibrium distance between bases
in a Watson-Crick pair. Here we analyze the Yakushevich model without $\ell_0
\to 0$. The model still supports soliton solutions indexed by two winding
numbers $(n,m)$; we discuss in detail the fundamental solitons, corresponding
to winding numbers (1,0) and (0,1) respectively.
