A Laterally Transferred Viral Gene Modifies Aphid Wing Plasticity

Area of Science:

• Evolutionary biology
• Genetics
• Ecology

Background:

• Organisms adapt to environmental changes by altering trait development, a phenomenon known as phenotypic plasticity.
• Genetic variation exists within plastic traits, allowing different genotypes to respond uniquely to environmental cues.
• The genetic mechanisms underlying adaptive plasticity remain largely unknown.

Purpose of the Study:

• To identify the genetic mechanisms responsible for variation in phenotypic plasticity.
• To investigate the role of laterally transferred genes in the pea aphid's plastic response to crowding.

Main Methods:

• Aphid genotype analysis for wing plasticity variation.
• Gene expression analysis (upregulation) in response to crowding.
• Gene knockdown experiments to confirm functional roles.
• Phylogenetic analysis to trace gene origins.

Main Results:

• Aphid genotypes exhibit significant variation in producing winged offspring due to crowding.
• Laterally transferred viral genes are upregulated in response to crowding, but only in highly plastic genotypes.
• Knocking down these viral genes impairs wing plasticity.
• Phylogenetic analysis suggests these genes originated from a virus that induces wing development in other aphid species.

Conclusions:

• Co-opted viral genes play a crucial role in modulating plastic phenotypes in pea aphids.
• Genes acquired from external sources can be repurposed to fine-tune the strength of environmentally sensitive traits.
• This study demonstrates that genes not originally involved in plasticity can evolve to control its expression and variation.