| 摘要 |
A method for sequencing DNA is presented which allows for a more even distribution of short and long strands of synthesized DNA. This results in a more even peak height allowing the reading of more sequence. The method uses a combination of at least two different types of DNA polymerase wherein a first DNA polymerase discriminates highly between dNTPs and ddNTPs and consequently incorporates ddNTPs only rarely and wherein a second DNA polymerase does not discriminate to a large extent between dNTPs and ddNTPs and will incorporate both nucleotides at approximately equal rates. The method further can incorporate cycle sequencing. The first DNA polymerase results in long pieces of DNA which can be further elongated or terminated by the second DNA polymerase in subsequent rounds of sequencing thereby allowing for more effective incorporation of label into longer pieces of DNA than is accomplished by most prior art methods of sequencing. Use of a proper ratio of the two DNA polymerases and use of a proper ratio of dNTPs to ddNTPs results in a more even distribution of label across a range of short to long strands of synthesized DNA than is accomplished by prior art methods thereby enabling a better reading of longer stretches of sequence from a single reaction or set of reactions. |
