A method for determining sequences from sense and antisense strands of a nucleic acid, including (a) providing a nucleic acid cluster attached to a solid support, wherein the nucleic acid cluster includes a sense strand and an antisense strand of a concatemer, the concatemer including multiple copies of a sequence unit, the sequence unit including a target sequence and a primer binding site; (b) hybridizing a primer to a primer binding site in the antisense strand; (c) extending the primer along the antisense strand to determine the sequence from at least a portion of the target sequence in the antisense strand; (d) hybridizing a second primer to a primer binding site in the sense strand; and (e) extending the second primer along the sense strand to determine the sequence from at least a portion of the target sequence in the sense strand.