The evolution of microRNA-regulation in duplicated genes facilitates expression divergence

TL;DR

This study investigates how microRNA regulation evolves in duplicated genes in D. melanogaster, revealing that microRNA-targeted genes tend to avoid duplication and that divergence in gene sequences correlates with changes in microRNA regulation, facilitating expression divergence.

Contribution

It uncovers the relationship between gene duplication, sequence divergence, and microRNA regulation, highlighting microRNAs' role in evolving expression divergence.

Findings

MicroRNA-targeted genes tend to avoid duplication.

Divergent genes are less likely to be microRNA targets.

MicroRNA regulation correlates with gene expression divergence.

Abstract

Background: The evolution of microRNA regulation in metazoans is a mysterious process: MicroRNA sequences are highly conserved among distal organisms, but on the other hand, there is no evident conservation of their targets. Results: We study this extensive rewiring of the microRNA regulatory network by analyzing the evolutionary trajectories of duplicated genes in D. melanogatser. We find that in general microRNA-targeted genes tend to avoid gene duplication. However, in cases where gene duplication is evident, we find that the gene that displays high divergence from the ancestral gene at the sequence level is also likely to be associated in an opposing manner with the microRNA regulatory system - if the ancestral gene is a miRNA target then the divergent gene tends not to be, and vice versa. Conclusions: This suggests that miRNAs not only have a role in conferring expression robustness, as was suggested by previous works, but are also an accessible tool in evolving expression divergence.