We review recent developments in spaced seed design for cross-species sequence
alignment. We start with a brief overview of original ideas and early techniques, and then focus on
more recent work on finding accurate (sensitive and specific) seeds for cross-species cDNA-to-genome
alignment. These recent developments include methods and models for estimating seed specificity
and determining sensitive and specific seeds, finding seeds that can be applied to a wide range of
comparisons, and applying seed models to other computational biology areas, such as gene finding.