Table 2.

λ genetic elements

Element	Description and ref.
cI857	Temperature-sensitive allele of cI for heat induction of lysogens (20)
P80	Suppressor-sensitive (sus) allele of P that provides a partial replication block (21)
S7	sus allele of S suppressible only by SuIII (22)
b1451	Δredα (23)
red329	sus mutation in redα (24)
red113	sus mutation in redβ (24)
gam210	sus mutation in redγ (25)
red15	Δredα/β (23)
nin5	ΔninR region (26)
SR1::XhoI	Insertion of an XhoI linker at position 21226 (∗)
XhoI::EcoRI	Mutant XhoI site (∗)

^*F.W.S. and M.M.S., unpublished work.