Organisms with DNA genomes encode one or more DNA polymerases that are essential enzymes for chromosome replication, DNA repair and recombination. The ability of DNA polymerases to copy DNA templates has been exploited in a variety of in vitro reactions to sequence, amplify, mutate, label and recombine DNA, and in several other applications that are fundamental to molecular biology. Because natural DNA polymerases may have activities that interfere with in vitro applications or their substrate specificity is too narrow, DNA polymerases have been modified for specific applications. Patents are reviewed here on natural and variant DNA polymerases and their uses.