Abstract
Three evolutionary variants of simian virus 40 (SV40), cloned by complementation with temperature-sensitive SV40 mutants, have been mapped by restriction endonuclease analysis and by electron microscopic heteroduplex mapping. One of the variants contains a deletion of most of the “late” region of the genome, and the other two contain nonidentical deletions within the “early” region. Each of the variants has a distinctive duplication of a DNA segment which includes the initiation site for DNA replication. Based on the physical maps of these genomes, a recombinational mechanism is suggested for the generation of variants; once generated, encapsidatible molecules with duplications of the replication initiation site would have a selective growth advantage. One variant contains one of its two initiation sites close to the site where SV40-DNA replication normally terminates. In this variant, however, replication appears to terminate 180° from the initiation point. Therefore, unlike initiation, termination of SV40-DNA replication is probably not sequence specific.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
