Mosquito genomes are frequently invaded by transposable elements through horizontal transfer

Area of Science:

• Genomics
• Molecular Evolution
• Bioinformatics

Background:

• Transposable elements (TEs) are mobile genetic sequences found in most eukaryotic genomes.
• Characterization of TEs is limited to a few model organisms due to their complexity.
• Understanding TE dynamics is crucial for comprehending genome evolution and variability.

Purpose of the Study:

• To characterize transposable elements (TEs) in 24 mosquito species genomes.
• To investigate the inheritance patterns and horizontal transfer of TEs among mosquitoes.
• To explore TE exchanges between mosquitoes and other taxa.

Main Methods:

• De novo and homology-based TE characterization.
• Genomic analysis of 24 mosquito species.
• Comparative genomics across diverse taxa (>32,000 genomes).

Main Results:

• TEs comprise over 40% of genomes in Aedes and Culex species, but vary in Anopheles.
• At least 24 TE superfamilies were identified, with Class I elements being most abundant.
• Extensive horizontal transfer of 172 TE families among mosquitoes, and between mosquitoes and other phyla (Cnidaria, Nematoda) and subphyla (Chelicerata, Crustacea) was observed.
• The worm Wuchereria bancrofti was identified as a vector for Tc1-mariner element spread among Anopheles species.

Conclusions:

• Transposable elements are frequently exchanged via horizontal transfer among mosquito species.
• Horizontal TE transfer significantly influences mosquito genome size and genetic variability.
• Mosquitoes act as vectors for TE dissemination across a wide range of organisms.