Cost-benefit analysis of recombination and its application for understanding of chiasma interference

A cost-benefit analysis of recombination was undertaken. The beneficial eff ects of crossing-over are proportional to the frequency of recombinant offs pring, while its harmful effects (errors of crossing-over leading to mutati ons) are proportional to the number of crossover exchanges. An equilibrium point should exist where the beneficial effects of crossing-over are balanc ed by its harmful effects. It is suggested that natural selection sustains a number of crossover exchanges per meiosis at the level that provides high est benefit-cost difference. Chiasma interference prevents the arising of c losely located exchanges which are less effective in the production of reco mbinants than exchanges separated by some "interference distance". Computer simulation shows that chiasma interference increases the recombination eff ectiveness of the multiple crossover exchanges as compared to the case with out interference. (C) 2001 Academic Press.