title: The role of Chi mutations in the Spi- phenotype of phage lambda: lack of evidence for a gene delta.
abstract: Lambda red- gam- makes a small plaque on P2 lysogens (the partial Spi- phenotype). It has been proposed that inactivation of an additional gene delta, mapping in the recombination region, makes the plaque bigger (the full Spi- phenotype) (Zissler et al., 1917b). The present paper demonstrates that the Chi mutation in lambda (Stahl et al., 1975) confers upon red- gam- phage the full Spi- phenotype and that the deletion of the region of the chromosome attributed to delta does not. It appears unnecessary to invoke a gene delta in the Spi- phenotype.
mesh_terms: D002872:Chromosome Deletion; D002874:Chromosome Mapping; D003090:Coliphages / Q000254:growth & development; D004926:Escherichia coli; D005796:Genes; D005816:Genetic Complementation Test; D008242:Lysogeny; D009154:Mutation; D010641:Phenotype; D011995:Recombination, Genetic