# The P-element strikes again: the recent invasion of natural Drosophila simulans populations

## TL;DR

The P-element, a transposable element, has recently invaded Drosophila simulans populations, likely from Drosophila melanogaster, offering insights into transposable element spread and defense.

## Contribution

The paper reports the recent horizontal transfer of the P-element into Drosophila simulans, providing a new model system for studying transposable element dynamics.

## Key findings

- P-elements in D. simulans were likely acquired from D. melanogaster via a single horizontal transfer event.
- P-element insertions in D. simulans are enriched in putative origins of replication, similar to D. melanogaster.
- The P-element is processed in the germline of D. simulans, indicating functional activity.

## Abstract

The P-element is one of the best understood eukaryotic transposable elements. It invaded Drosophila melanogaster populations within a few decades, but was thought to be absent from close relatives, including D. simulans. Five decades after the spread in D. melanogaster, we provide evidence that the P-element has also invaded D. simulans. P-elements in D. simulans appears to have been acquired recently from D. melanogaster probably via a single horizontal transfer event. Expression data indicate that the P-element is processed in the germline of D. simulans, and genomic data show an enrichment of P-element insertions in putative origins of replication, similar to that seen in D. melanogaster. This ongoing spread of the P-element in natural populations provides an unique opportunity to understand the dynamics of transposable element spreads and the associated piRNA defense mechanisms.