Population genomics of the Wolbachia endosymbiont in Drosophila melanogaster

TL;DR

This study uses genome sequencing of Drosophila melanogaster from multiple continents to analyze Wolbachia infection patterns, revealing maternal transmission, incomplete lineage replacement, and a common ancestor dating back around 8,000 years.

Contribution

It provides a comprehensive genomic analysis of Wolbachia in D. melanogaster, uncovering transmission dynamics and historical lineage replacements.

Findings

Wolbachia and mitochondrial genomes show congruent phylogenies.

Most recent common ancestor of Wolbachia and mtDNA dates to ~8,000 years ago.

Evidence of recent incomplete global replacement of Wolbachia lineages.

Abstract

Wolbachia are maternally-inherited symbiotic bacteria commonly found in arthropods, which are able to manipulate the reproduction of their host in order to maximise their transmission. Here we use whole genome resequencing data from 290 lines of Drosophila melanogaster from North America, Europe and Africa to predict Wolbachia infection status, estimate cytoplasmic genome copy number, and reconstruct Wolbachia and mtDNA genome sequences. Complete Wolbachia and mitochondrial genomes show congruent phylogenies, consistent with strict vertical transmission through the maternal cytoplasm and imperfect transmission of Wolbachia. Bayesian phylogenetic analysis reveals that the most recent common ancestor of all Wolbachia and mitochondrial genomes in D. melanogaster dates to around 8,000 years ago. We find evidence for a recent incomplete global replacement of ancestral Wolbachia and mtDNA lineages, which is likely to be one of several similar incomplete replacement events that have occurred since the out-of-Africa migration that allowed D. melanogaster to colonize worldwide habitats.