TABLE 2.

Suppression of the cosN G₂C mutation: crosses between λ cosN G₂C C₁₁G and cloned DNA segments of λ A⁺, λ A-E₅₁₅G, λ A-N₅₀₉K, or λ A-R₅₀₄C^a

Sequence of cloned segment (bp)	Allele	Amino acid change(s) in gpA	PFU/viable cell
1818–2556	A+	None	<5.0 × 10−6
458–5548	A-E515G	E515G	1.1 × 10−1
2212–2847	A-N509K	N509K	4.1 × 10−3
2190–2556	A-R504C	R504C	7.7 × 10−4b
1818–2556	A-R504C	P416S, R504C	1.9 × 10−3b
1818–2190		P416S	<5.3 × 10−5b

^aCrosses were performed with plasmids in an MF1427 (λ cosN G₂C C₁₁G gal⁺ att⁺ cI857) lysogen and were plated on MF1972 for plaques. The higher frequency of recombinants for A-E₅₁₅G is a reflection of the larger λ DNA insert in the plasmid used (5 kb). 

^bThese lysates were plated on MF1427 for recombinants forming normal-sized plaques.