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How do the natural DNA base pairs A-T and C-G work in genetic systems?

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synthetic biology; Mycoplasma mycoides JCVI-syn1.0 — synthetic biology A scanning electron micrograph of cells of *Mycoplasma mycoides* JCVI-syn1.0—a synthetic bacterium.

In genetic systems, the natural DNA base pairs—adenine (A) with thymine (T) and cytosine (C) with guanine (G)—function as the fundamental structural and informational units of the DNA double helix.12

These pairs are held together by weak hydrogen bonds, which connect the two antiparallel strands of the molecule. This specific pairing, known as Watson-Crick base-pairing, creates a stable "lock-and-key" fit that is essential for the molecule's helical configuration.231

The biological significance of these pairs lies in their role in heredity:
* Replication: Because the strands are complementary, they can separate and serve as templates for the synthesis of new, identical strands, ensuring genetic information is passed on with high fidelity.23
* Information Coding: The specific sequence of these base pairs along the DNA molecule represents the coded information that guides the development and function of organisms.2

In the field of synthetic biology, researchers study these natural pairs to understand biological "bricks" and have even attempted to expand the genetic code by creating synthetic DNA with additional, non-natural base pairs.4