Large-Scale Annotation and Evolution Analysis of MiRNA in Insects

Area of Science:

• Evolutionary Biology
• Genomics
• Molecular Biology

Background:

• Insects display remarkable morphological diversity, with wings and metamorphosis being key evolutionary innovations.
• MicroRNAs (miRNAs) are crucial for gene regulation, canalization, and phenotype heritability, yet their evolutionary history in insects remains largely unexplored.

Purpose of the Study:

• To comprehensively annotate and analyze the evolutionary dynamics of microRNA repertoires across 152 arthropod species, with a focus on insects.
• To investigate the relationship between miRNA gene presence/absence, insect evolution, and the emergence of key morphological traits.

Main Methods:

• Utilized small RNA sequencing (RNA-seq) data and homology searching to identify and classify miRNA genes.
• Analyzed miRNA gene family presence/absence patterns across a broad phylogenetic range of arthropods.

Main Results:

• Identified 16,212 miRNA genes across 152 species, classifying them into conserved and lineage-specific families.
• Discovered significant miRNA losses in morphologically simplified insects (e.g., scale insects) and gains associated with the evolution of wings, metamorphosis, and specific insect orders (Hymenoptera, Lepidoptera).
• Phylogenetic analysis revealed homoplastic loss of conserved miRNAs, impacting phylogenetic reconstruction, and identified miRNA gains coinciding with major insect evolutionary events.

Conclusions:

• Provides a foundational dataset and evolutionary analysis of insect miRNAs, highlighting their role in morphological innovation.
• Suggests miRNA evolution, including losses and gains, is intricately linked to insect diversification and the development of complex traits.
• These findings are critical for future research on miRNA functions underlying insect biodiversity and evolution.