Methods, systems, and compositions for nucleic acid sequencing

A method for processing or analyzing a double-stranded nucleic acid molecule, comprising:

• (a) providing a circularized double-stranded nucleic acid molecule comprising a double-stranded nucleic acid molecule coupled to a double-stranded adapter, wherein said double-stranded adapter comprises a nicking site within a sense strand or an anti-sense strand of said double-stranded adapter;
• (b) subjecting said circularized double-stranded nucleic acid molecule to an extension reaction from said nicking site, to generate a growing strand having sequence complementarity to at least a portion of a strand of said double-stranded nucleic acid molecule;
• and
• (c) obtaining sequence information of at least a portion of said growing strand.