Exploring horizontal transfer of mariner transposable elements among ants and aphids

Area of Science:

• Genetics
• Evolutionary Biology
• Entomology

Background:

• Aphids and ants exhibit close spatial and temporal relationships, fostering potential for horizontal gene transfer.
• Myrmar-like mariner elements have been previously identified in select ant and aphid species.

Purpose of the Study:

• To investigate the presence of Myrmar-like mariner elements in new ant and aphid species.
• To analyze the likelihood of horizontal transfer events of these elements between aphids and ants.

Main Methods:

• Isolation of Myrmar-like elements from five aphid and six ant species.
• Sequence similarity analysis of isolated elements.
• Phylogenetic analysis of Myrmar-like elements.
• Analysis of the putative protein encoded by the elements.

Main Results:

• Full-length Myrmar-like mariner elements with high similarity were found in aphids (Aphis nerii, Aphis spiraecola, Brachycaudus cardui, Rhopalosiphum maidis) and ants (Lasius grandis, Lasius niger), despite their deep evolutionary divergence.
• Frequent mutualistic relationships between Lasius ants and aphid species correlate with element presence.
• Mariner elements with internal deletions were identified in multiple aphid and one ant species, indicating complex evolutionary origins potentially involving horizontal transfer.
• Myrmar-like elements were also found in phylogenetically distant insects and a crustacean, supporting widespread horizontal transfer.

Conclusions:

• Horizontal transfer events are likely responsible for the shared Myrmar-like mariner elements between distantly related aphids and ants.
• Mutualistic interactions between these insect groups may facilitate the transmission of these mobile genetic elements.
• The presence of these elements across diverse taxa suggests a significant role for horizontal gene transfer in insect evolution.