Methods for detecting and sequencing of target double-stranded nucleic acid molecules, nucleic acid probes and arrays of probes useful in these methods, and kits and systems that contain these probes are provided. The methods involve hybridizing the nucleic acids or nucleic acids which represent complementary or homologous sequences of the target to an array of nucleic acid probes. These probes include a single-stranded portion, an optional double-stranded portion and a variable sequence within the single-stranded portion. The molecular weights of the hybridized nucleic acids of the set can be determined by mass spectroscopy, and the sequence of the target determined from the molecular weights of the fragments.