Dick Gordon may be right but strict left-right mosaics are very
spectacular and unusual. Check these references: Stern, C. 1968 Genetic
mosaics and other essays. Harvard University Press Cambridge, MA or
Gehring., W. J. ed. 1978 Genetic mosaics and cell differentiation.
Results and problems in cell differentiation. Vol. 9 Springer-Verlag,
Berlin, Heidelberg, New York.