Do viruses participate in the origin of group outbursts of gene mutations occurring in natural Drosophila populations?

It has been experimentally shown that different viruses apathogenic for Drosophila and unable to reproduce in it, and also highly polymerized DNA isolated from these viruses, act as effective mutagens when injected into the hemolymph of this insect. They induce numerous lethal and visible stable gene mutations. Some of them can be present in Drosophila natural populations. But these virus induced gene mutations or those induced by virus DNA never take part in the origin of group outbursts of gene mutation which are observed in Drosophila melanogaster natural populations. These mutability outbursts include only gene mutations induced by transpositions of mobile genetic elements. These mutations are usually unstable: they are apt to be converted to other allelic mutant states which are phenotypically differently expressed. Viruses which are endemic for Drosophila melanogaster and can reproduce in it take no part in the outbursts of gene mutations. They can only induce a small number of lethal and visible gene mutations which are stable and arise very infrequently. It seems probable that group outbursts of gene mutations in natural populations of Drosophila melanogaster are c49 a result of various environmental stresses which cause a rise in the frequency of transpositions of mobile genetic elements, this leading to the mutability outbursts of gene mutations.

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