The slow road to the eukaryotic genome

Area of Science:

• Genomics
• Evolutionary Biology
• Molecular Biology

Background:

• The eukaryotic genome's unique mosaic structure suggests complex evolutionary origins.
• Current theories include genome fusion or endosymbiotic events.
• Lateral gene transfer (LGT) is also proposed as a significant contributor.

Purpose of the Study:

• To investigate the role of successive lateral gene transfer events in shaping the eukaryotic genome.
• To evaluate whether LGT can explain the eukaryotic gene mosaic without necessarily invoking endosymbiosis.
• To reconstruct the ancestral appearance of genes on the prokaryotic phylogeny.

Main Methods:

• Phylogenetic studies of gene evolution.
• Reconstructions of ancestral gene appearances across prokaryotic lineages.
• Comparative analysis of gene acquisition timelines.

Main Results:

• Phylogenetic patterns supporting genome fusion can also result from sequential LGT events.
• Eukaryotic genes originated at different times and from diverse prokaryotic lineages.
• Genes were not available in a single ancestral prokaryotic lineage for fusion.

Conclusions:

• Successive lateral gene transfer events provide a robust explanation for the eukaryotic genome's mosaic structure.
• The acquisition of genes via LGT is linked to their immediate adaptive value.
• Further research into ancestral features like the eukaryotic splicesome may illuminate eukaryotic niche establishment.