title: Transition from a heterozygous to a homozygous state of a pair of loci in the inverted repeat sequences of the L component of the herpes simplex virus type 1 genome.
abstract: The behavior of herpes simplex virus type 1 heterozygous isolates, in which the two inverted repeats of the L component (RL) were differentiated by a polymorphism marker (the presence [type B] or absence [type A] of a SalI site), was investigated. The progeny viruses derived from the heterozygote (A/B) consisted of heterozygotes (A/B), type A homozygotes (A/A), and type B homozygotes (B/B). The heterology between RL, albeit tolerated, was unstable, as is the case with heterology between the repeats of the S component. The two repeats TRL (terminal) and IRL (internal) were equipotent in generating homozygotes from a heterozygote. Data obtained from an analysis of 426 progeny viruses derived from heterozygous clones supported the hypothesis that the two loci in RL of a herpes simplex virus type 1 genome are determined as a random combination of the corresponding two loci in RL of the parent virus and that the ratio of heterozygotes/type A homozygotes/type B homozygotes in the progeny viruses from a heterozygote is expected to be 2:1:1. An ephemeral dominance of one type of homozygote over the other was observed in subclones from several heterozygous clones.
mesh_terms: D000818:Animals; D003001:Cloning, Molecular; D004279:DNA, Viral / Q000302:isolation & purification; D005814:Genes, Viral; D006579:Heterozygote; D006720:Homozygote; D012091:Repetitive Sequences, Nucleic Acid; D018139:Simplexvirus / Q000235:genetics*; D014709:Vero Cells
chemical_list: D004279:DNA, Viral