Sunday, December 27, 2015

Naturally occurring 'GM' butterflies produced by gene transfer of wasp-associated viruses

I read about this in New Scientist magazine for Sept. 26, 2015.

Date: September 17, 2015
Source: PLOS
Research teams have discovered that genes originating from parasitic wasps are present in the genomes of many butterflies. These genes were acquired through a wasp-associated virus that integrates into DNA. Wasp genes have now been domesticated and likely play a role in in protecting butterflies against other pathogenic viruses.


To reproduce, braconid wasps lay their eggs inside caterpillars and inject a 'giant virus' named bracovirus to circumvent the caterpillars' immune response. Bracoviruses can integrate into the DNA of parasitized caterpillars and control caterpillar development, enabling wasp larvae to colonize their host.


The integrated genes that have been identified are not only remnants: results obtained suggest that they play a protective role against other viruses present in nature, baculoviruses. Strikingly the domestication of genes harboured by bracoviruses is not limited to " viral " genes, some of them originated from the wasp


Given that tens of thousands of parasitic wasp species, each associated with a unique bracovirus, parasitize virtually all lepidopteran species, it is likely that the described phenomenon is general and that different gene transfers occur regularly in nature. Beyond the interest these lateral gene transfers evoke in evolutionary biology, these results highlight the risk gene transfers could cause, in case GM-parasitoid wasps are produced, as genes artificially introduced into wasp species used for biological control could be transferred into the genomes of the targeted pests. Production of GM wasps expressing insecticide resistance for biological control of pests, for example, could lead to involuntary transmission of this resistance to the herbivorous insects.

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