Tag: lepidoptera

23pairsofchromosomes:

Wasp uses Virus to Genetically Modify Butterfly

Many of us are familiar with the monarch butterfly (Danaus plexippus), but a research group is France has identified the genes for C-type lectins in this species most likely originated from parasitic wasps that are known to lay their eggs in the caterpillars of this species. These proteins are carbohydrate binding proteins with a large number of roles in cells. 

Parasitic wasps are common in the insect world, with virtually all Lepidopteran species being targets for parasitism. It is believed that ~100 million years ago a wasp ancestor domesticated the bracovirus, and now these parasitic wasps employ it as a biological weapon against the caterpillars. The virus is produced in the wasp’s ovaries and acts as a vector for horizontal gene transfer (HGT). In the eukaryotic world, it is fairly rare for such an exchange of DNA between organisms.

The virus has long since lost its ability to generate a successful capsid, and as a result is reliant on the wasp’s ovaries for replication. The virus is injected into the host along with the wasp’s eggs where the domesticated virus promotes the growth of wasp progeny within the caterpillar by inhibiting its immune system. Each wasp lineage has its own set of virulence determinants encoded by the virus.

Integration of viral DNA may occur occasionally, if a caterpillar host manages to successfully defend itself against a parasitic attack or if the wasp lays its eggs in the wrong target. In both cases the caterpillar may go onto to develop into a moth or butterfly in possession of viral and wasp derived genes as seen in the monarch butterfly.

Figure showing the hypothesised process for HGT to occur between wasps and Lepidopteran species (Source)

Source: Plos Genetics – 

Recurrent Domestication by Lepidoptera of Genes from Their Parasites Mediated by Bracoviruses