The invention provides a new method for DNA sequencing called “natural sequencing by synthesis” (nSBS). According to the method, DNA that includes a desired sequence is synthesized using a dNTP mix with a small percentage of fluorescently-labeled nucleotides. The fluorescent label is cleavable. In contrast to previous methods that utilize 100% labeled nucleic acids, use of a small percentage of labeled nucleic acids minimizes the distortion of the natural structure of the extending DNA strand and the DNA polymerase. Using the disclosed methods with less than 10,000 copies of template DNA and 10% of the nucleotides labeled, long homopolymer stretches up to 20 bases can be sequenced with high accuracy and Q20 (with 99% accuracy) read lengths of up to 1,000 bases can be achieved. A Q20 read length of greater than 100 bases can potentially be achieved, even if the sequencing is performed with 1,000 copies of a template and 10% of the nucleotides labeled.