To increase the scope of natural biosystem, nucleic acids have been intensively modified. One direction includes the development of a synthetic alternative to the native DNA and RNA, denoted Xenobiotic nucleic acids (XNAs) that are able to store and transfer genetic information either by base-modification or backbone-modification. Another line of research aims to develop alternative third base pair additional to natural A:T and G:C. These unnatural base pairs (UBPs) can store increased information content encoded in three base pairs. This review outlines the recent progress made towards XNA and UBP applications as new components of the genomic DNA as well as biostable aptamers. New achievements in the replacement of a bacterial genome by unnatural non-canonical nucleotides are also described.

为了增加天然生物系统的范围，已经对核酸进行了深入的修饰。一个方向包括开发替代天然DNA和RNA的合成替代物，称为异种生物核酸（XNA），其能够通过碱基修饰或骨架修饰来存储和转移遗传信息。另一项研究旨在开发除天然A：T和G：C之外的替代第三碱基对。这些非自然碱基对（UBP）可以存储以三个碱基对编码的增加的信息内容。这篇综述概述了在XNA和UBP作为基因组DNA的新成分以及生物稳定适体方面的最新进展。还描述了用非天然的非规范核苷酸替代细菌基因组的新成就。