Evolution of DNA Double-Strand Break Repair by Gene Conversion: Coevolution Between a Phage and Restriction-Modification System

Yahara K, Horie R, Kobayashi I, & Sasaki A (2007). Evolution of DNA Double-Strand Break Repair by Gene Conversion: Coevolution Between a Phage and Restriction-Modification System. IIASA Interim Report. IIASA, Laxenburg, Austria: IR-07-060

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Abstract

The necessity to repair genome damage has been considered to be an immediate factor responsible for the origin of sex. Indeed, attack by a cellular restriction enzyme of invading DNA from several bacteriophages initiates recombinational repair by gene conversion if there is homologous DNA. In the present work, we modeled the interaction between a bacteriophage and a bacterium carrying a restriction enzyme as antagonistic coevolution. We assume a locus on the bacteriophage genome has either a restriction-sensitive or a -resistant allele, and another locus determines whether it is recombination/repair-proficient or -defective. A restriction break can be repaired by a co-infecting phage genome if one of them is recombination/repair-proficient. We define the fitness of phage (resistant/sensitive and repair-positive/-negative) genotypes and bacterial (restriction-positive/-negative) genotypes by assuming random encounter of the genotypes, with a given probabilities of single and double infections, and the costs of resistance, repair and restriction. Our results show the evolution of the repair allele depends on b1 / b0 , the ratio of the burst size b1 under damage to host cell physiology induced by an unrepaired double-strand break to the default burst size b0 . It was not until this effect was taken into account that the evolutionary advantage of DNA repair became apparent.

Item Type: Monograph (IIASA Interim Report)
Research Programs: Evolution and Ecology (EEP)
Depositing User: IIASA Import
Date Deposited: 15 Jan 2016 08:40
Last Modified: 07 Nov 2016 13:15
URI: http://pure.iiasa.ac.at/8398

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