Analysis Of The Effect Of Repetitive DNA Sequence Characteristics On Sequencing Results

It is prone to sequencing signal termination, weakening or overlapping peaks when sequencing samples containing repetitive DNA sequences with ABI3730xl automatic sequencer. It is easy to cause sequencing failures. In this thesis, test samples containing microsatellite (short tandem repetitive DNA sequences) are divided into four types according to the repeating characteristics, including single nucleotide microsatellite, dinucleotide microsatellite, trinucleotide microsatellite and polynucleotides microsatellite. General experimental conditions and optimized experimental conditions (changing the PCR reaction conditions as well as adding dGTP components) were used for sequencing and then the sequencing results were compared.Four groups of sequencing results showed that increasing PCR reaction annealing time to 15 s, reaction time to 10 s and reaction cycles count to 80 and adding dGTP components can result to the best sequencing effect. The sequencing failed samples in ordinary experimental conditions can be sequenced successfully in this optimized condition. For the samples tested in this thesis, the Quality value of the sequencing results increased from 57.8% to 94.3%. Moreover, nucleotide sequences of the test samples can be obtained. The results are very good and has important reference value for the others.