Abstract: The present disclosure discloses a method for modifying a DNA by utilizing a glycosylase and an oxyamine compound, including the following steps: conducting solid phase synthesis of a DNA strand carrying a non-canonical base; reacting the DNA strand carrying a non-canonical base under the catalysis of the glycosylase which selectively recognizes the non-canonical base, to produce a DNA strand carrying an abasic site; and reacting the DNA strand carrying the abasic site with the oxyamine compound to generate a DNA modified with a chemical functional group. This method can realize diverse site-directed modification of the DNA, can be used to study the base structure-function relationship of a functional DNA, and construct a functional DNA with higher activity. The present method is simple and easy to use, and can reduce the cost and the time required for modification. The modified functional DNA has higher activity and can provide better tool molecules for biotechnology, disease diagnosis and treatment.

Abstract: Methods and compositions for replication of threose nucleic acids (TNAs) are described. The described methods include a method for transcribing a DNA template into a TNA, and a method for reverse transcribing a threose nucleic acid into a cDNA.