Evolution of photosynthetic prokaryotes: a maximum-likelihood mapping approach

Area of Science:

• Microbiology
• Evolutionary Biology
• Genomics

Background:

• Reconstructing the early evolution of photosynthesis is challenging due to its ancient origins.
• Geological records provide some insights, but molecular genetic techniques are crucial for inference.
• Recent advances in genome sequencing offer comprehensive data from photosynthetic bacteria.

Purpose of the Study:

• To investigate the role of horizontal gene transfer (HGT) in the evolution of photosynthetic bacteria.
• To perform phylogenetic comparisons across all five bacterial phyla containing photosynthetic members.
• To understand the evolutionary history and genome structure of early photosynthetic organisms.

Main Methods:

• Whole genome comparisons were conducted using maximum likelihood analysis.
• 527 unique sets of orthologous genes were analyzed from representatives of all five photosynthetic bacterial phyla.
• Phylogenetic signals were examined to infer evolutionary relationships and gene transfer events.

Main Results:

• Horizontal gene transfer (HGT) has played a significant role in the evolution of photosynthetic bacteria.
• Bacterial genomes exhibit mosaic evolutionary histories due to extensive gene exchange.
• A minor phylogenetic signal suggests a potential core of conserved genes or preferential gene exchange.

Conclusions:

• HGT is a major driver shaping the genomes and evolution of photosynthetic bacteria.
• Understanding HGT is key to reconstructing the early evolution of photosynthesis.
• Further research is needed to elucidate the nature of the observed phylogenetic signal and gene exchange patterns.