Abstract
Terminal deoxynucleotidyl transferase (TdT), a unique DNA polymerase, can elongate DNA by adding deoxynucleotides to the 3' terminal of a DNA chain in a template-independent manner. Owing to their remarkable DNA synthesis activity, TdTs have promoted the development of numerous nucleic acid-based methods, tools, and associated applications, attracting broad interest from both academia and industry. This review summarizes and discusses the recent research on TdTs, including their biochemical characteristics, enzyme engineering, and practical applications. New insights and perspectives on the future development of TdTs are provided.