Abstract: The present invention provides a novel method for labeling and sequencing nucleic acid molecules, particularly DNA molecules in which an internally labeled, partially extended primer is elongated in a cycled primer extension reaction. An unlabeled DNA primer is contacted with a DNA template in the presence of suboptimal amounts of four dNTPs, one of which is labeled with a detectable marker which may be a fluorescent or visible fluorophor, and infared fluorophor or a radioactive label. This small, labeled primer extension product is then transferred to a new reaction where chain terminated primer extension products for DNA analysis are prepared.