A novel DNA rearrangement has been characteriszed that is both a direc
t and inverted repeat. This rearrangement involves the 2-fold duplicat
ion of a plasmid sequence adjacent to the site of insertion of a long
palindrome. The sequence of this rearrangement suggests that it has ar
isen by strand slippage from the leading to the lagging strand of the
replication fork as a consequence of the presence of the long palindro
me.