Elongation of Trinucleotide Repeats by DNA Polymerase

摘要

The wide present simple repetitive sequences in genomes are significant for studying molecular evolution, genetic diversity, and some hereditary diseases. Here, elongation of 64 (3~4) kinds of 18 nucleotides long sequences with trinucleotide tandem repeats by DNA polymerase was studied. The result showed that all of the repeats, apart from several strands made up with single nucleotide, could be elongated, although the efficiency depended on the sequences and reaction temperatures. More GC content required a higher temperature for efficient elongation. For double strands, elongation products had a narrow size distribution, and the length of synthesized DNA increased linearly with reaction time. Single-stranded sequences could also be elongated with even higher efficiency, and products longer than 10 kb were obtained in several hours. Our results are promising to be used for explanation of molecular evolution, as well as unusual amplification of repetitive sequences during gene amplification and detection.