Table 1.

Template strand requirements of X-family polymerases

Proposed activities	Template strand requirement	pol β	pol λ	pol μ	Tdt
a	Continuous template	Yes	Yes	Yes	No
b	Gapped template, primer terminus paired with template	No	Yes	Yes	No
c	Primer terminus not paired with template, incoming nucleotide instructed by template	No	No	Yes	No
d	Incoming nucleotide not instructed by template	No	No	Limited	Yes