  The one-bit deletion and duplication channel is investigated. An input to
this channel consists of a block of bits which experiences either a deletion,
or a duplication, or remains unchanged. For this channel a capacity expression
is obtained in a certain asymptotic regime where the deletion and duplication
probabilities tend to zero. As a corollary, we obtain an asymptotic expression
for the capacity of the segmented deletion and duplication channel where the
input now consists of several blocks and each block independently experiences
either a deletion, or a duplication, or remains unchanged.
