Patent ID: 7528241

Claim:
A kit comprising a) a first double stranded (ds) nucleic acid molecule, which comprises a first topoisomerase covalently bound at a 3′ terminus of a first end, and a second topoisomerase covalently bound at a 3′ terminus of a second end, said first end further comprising a first 5′ overhang and said second end further comprising a blunt end, a 3′ thymidine overhang, or a second 5′ overhang, wherein said first 5′ overhang is different from said second 5′ overhang; and b) a plurality of second ds nucleic acid molecules, wherein each ds nucleic acid molecule in the plurality comprises a first blunt end, and wherein the first blunt end comprises a 5′ nucleotide sequence complementary to the first 5′ overhang of the first ds nucleic acid molecule.