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The rule of the ring
Author(s) -
Thomas C. A.
Publication year - 1967
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1040700404
Subject(s) - superhelix , circular dna , duplex (building) , dna , biology , molecule , double stranded , linear molecular geometry , stereochemistry , genetics , physics , chemistry , genome , dna replication , gene , quantum mechanics , dna supercoil
Different species of viruses contain linear or circular DNA molecules. The circular molecules are either single‐chained or circular duplexes. The linear molecules from various species are always duplex. However, they may be either unique or circularly permuted collections of sequences. All species of linear duplexes that can be successfully tested can be shown to be terminally repetitious. The two temperate phages that have been studied (λ and P22) are unique and permuted collections, respectively. Shortly after infection both of these molecules form closed helical rings (superhelices). Certain virulent phages show no evidence of superhelix formation. How unique and permuted collections are produced at maturation is a puzzle. In this respect, it is of interest that P22 is a generalized transducing phage, whereas λ is a specialized transducing one.