On the Genetic Recombination of Bacteriophage ΦX174 DNA Molecules

Author: Benbow, Robert Michael

Year: 1972

Degree: Dissertation (Ph.D.)

Advisor: Sinsheimer, Robert L.

Committee Member: Unknown, Unknown

Option: Biology; Chemistry

DOI: 10.7907/M0E3-WG80

Abstract

Genetic recombination between two [phi]X174 parental replicative form DNA molecules primarily occurs by the following sequence of events: (i) a single strand scission in one HF DNA molecule; (ii) displacement synthesis; (iii) unimolecular branch migration; (iv) attack; (v) formation of a hydrogen bonded joint molecule; (vi) bimolecular branch migration and further DNA (repair?) synthesis; (vii and viii) covalent bond formation and single strand scission (order not certain); (ix) restoration of recombinant DNA molecules to the parental HF configuration. The net result is an asymmetric non-reciprocal recombination event yielding one parent and one recombinant. The average net DNA synthesis is less than 600 nucleotides; breakage and reunion occurs; over 50% of all genetic exchanges involve regions less than 4.00 nucleotides in length. Single strand insertion is (probably) the most common recombination event. Recombinant formation is complete at or shortly after the initiation of progeny HF DNA synthesis; the completed recombinant DNA molecule and surviving parental molecule then resume normal [phi]X174 DNA replication.

A (minor) secondary recombination mechanism exists in which recombinant formation occurs between [phi]X174 progeny HF DNA molecules.

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