positive epistasis
Trindade S, Sousa A, Xavier KB, Dionisio F, Ferreira MG & Gordo I 2009 Positive epistasis drives the acquisition of multidrug resistance. PLoS Genet 5:e1000578.
- while epistasis between gene deletions has been the focus of recent research, interactions between randomly selected alleles, which are of the greatest evolutionary interest has not
- a signature of pervasive positive epistasis amongst alleles that confer resistance to antibiotics
- epistatic interactions are allele specific
- a significant fraction of resistant mutations can be beneficial in certain resistant genetic backgrounds
- some double resistances entail no measurable cost
- some allelic combinations are hotspots for rapid compensation
- an extra layer of complexity on epistatic patterns previously unrecognized
- since it is hidden in genome-wide studies of genetic interactions using gene knockouts
- within hundreds of generations, mutations which compensate for the cost of antibiotic resistance (compensatory) are more likely to occur than revertants
- sign epistasis might have an important role for the evolution of antibiotic resistance
