Nucleic acid techniques are disclosed. Embodiments include modified nucleotides with oligonucleotide adapters that are coupled via cleavable linkers. Incorporation of the modified nucleotide at a 3′ end of a nucleic acid permits end-adapterization via ligation of a free 5′ end of the oligonucleotide adapter to a 3′ reactive group of the modified nucleotide and cleavage at the cleavable linker to liberate a free 3′ end.