Complex sentence: It most commonly pairs with thymine as an adenine-analogue, but can also pair with cytosine as a guanine-analogue; for this reason it is sometimes used in the laboratory for mutagenesis.
Split into simpler sentences: It most commonly pairs with thymine as an adenine-analogue, but can also pair with cytosine as a guanine-analogue;. For this reason it is sometimes used in the laboratory for mutagenesis.