polymerase the sequence of which is shown in fig3 single amino acid substitutions were introduced into full length or truncated polymerases as described davis fuller mamone amp huang wo 99 65938 incorporated herein by reference these substitutions are designated as d18a f667y e681r e681m e681h or e681w to describe the amino acid substitutions using the numbering corresponding to positions in taq polymerase each of the substituted polymerases was expressed purified and analyzed for uniformity of dye terminator incorporation in fluorescent sequencing studies as assayed by signal uniformity davis nelson kumar finn nampalli flick wo 01 14568 the e681r substitution was found to result in a substantial improvement of signal uniformity compared to the native dna polymerases this combined with the high stability make this polymerase an excellent choice for dna sequencing purposes the polymerases may be used to generate fluorescently labeled polynucleotides by using primed templates which templates may be used in chain termination sequencing or pcr as well understood by those skilled in the art and are described in wo 99 65938 previously incorporated herein by reference and u s pat no 5 210 036 incorporated herein by reference the following examples are for illustration purposes only and should not be used in any way to limit the appended claims.