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GENES ACQUIRED FROM HOST. "In some viruses this new variation is achieved by borrowing genetic material from their hosts. For example, influenza A virus has been observed to recombine with cellular RNA, resulting in increased pathogenicity for the hybrid viruses." http://www.sciencedirect.com/science/article/pii/S0042682215001580 View in LinkedIn

EXTREME CASES. "Some extreme cases of complementation between variants generated during quasispecies evolution that can greatly alter viral population structure or function have been described." http://www.sciencedirect.com/science/article/pii/S0042682215001580 View in LinkedIn

PATHOGENICITY. "Understanding RNA recombination is also important due to its potential to produce new hybrid strains, which may have novel properties and enhanced pathogenicity. Many recombinant RNA virus strains provide ample indication that recombination does exist in nature to generate new variation that enhances virus fitness." http://www.sciencedirect.com/science/article/pii/S0042682215001580 View in LinkedIn

SWARM REPLICATIVE ADVANTAGE. "Regarding complementation within mutant spectra, an initial observation was that fitness of biological viral clones was on average lower than fitness of the complete populations from which the clones were derived, indicating that the mutant ensemble had some replicative advantage over its individual components." http://www.sciencedirect.com/science/article/pii/S0042682215001580 View in LinkedIn

MUTATION TOLERANCE ENHANCED. "While the impact of viral recombination in evolution remain somewhat obscure, it is clear that these processes can also repair mutated genomes by purging mutations even in cells infected at low multiplicity. Thus, these “repairs” maintain viral fitness, and they may serve to increase the mutational tolerance of viral populations." http://www.sciencedirect.com/science/article/pii/S0042682215001580 View in LinkedIn

INCREASED DIVERSITY. "Many RNA viruses undergo recombination or reassortment during replication. In cells infected at high multiplicity, for example, this exchange of genetic information can increase genetic diversity by combining previously unique mutations into the same genome." http://www.sciencedirect.com/science/article/pii/S0042682215001580 View in LinkedIn

COMPLEMENTATION. "The efficiency of purifying (or negative) selection is the product of effective population size and the average mutational fitness effect(s). In large populations, strong selection will quickly purge mutants with lower fitness. Larger population sizes may also result in higher multiplicities of infection, where a given cell supports replication of at least two different genomes. Here, genetic complementation can increase the robustness of the viral population." http://www.sciencedirect.com/science/article/pii/S0042682215001580 View in LinkedIn

POPULATION SHIELD. "Most mutations have deleterious effects on viral fitness. Tolerance to mutational load determines the nature and extent of genetic diversity that can be maintained in the population. Thus, viral population diversity results from both the generation of mutations and the tolerance to them; these two factors together drive adaptation and virus evolution." http://www.sciencedirect.com/science/article/pii/S0042682215001580 View in LinkedIn

LOW FIDELITY. "The focus on mutation as a driving force in viral evolution has tended to overlook the tremendous cost of low replicative fidelity." http://www.sciencedirect.com/science/article/pii/S0042682215001580 View in LinkedIn

DIAGNOSTIC SOLUTION. "To overcome this limitation an experimental approach was developed that dramatically reduces sequencing errors.The basic premise of this method, called Circular Sequencing (or CirSeq). Using this approach, we are now able to estimate changes in mutation frequency of variants that exist in the population at very low levels. This opens an opportunity to determine fitness landscape at single nucleotide resolution." http://www.sciencedirect.com/science/article/pii/S0042682215001580 View in LinkedIn