We consider the mean electromotive force and a dynamo-generated magnetic fi
eld, taking into account the stretching of turbulent magnetic field lines b
y a shear flow. Calculations are performed by making use of the second-orde
r correlation approximation. In the presence of shear, the mirror symmetry
of turbulence can be broken; thus turbulent motions become suitable for the
generation of a large-scale magnetic field. Regardless of the shear law, t
urbulence can lead to a rapid amplification of the mean magnetic field. The
growth rate of the mean magnetic field depends on the length-scale: it is
faster for the fields with smaller length-scale. The mechanism considered i
s qualitatively different from the alpha dynamo, and can generate only a ma
gnetic field that is inhomogeneous in the direction of flow. In contrast to
the alpha dynamo, this mechanism also allows the generation of two-dimensi
onal fields. The suggested mechanism may play an important role in the gene
ration of magnetic fields in accretion discs, galaxies and jets.