Detection of horizontal gene transfer in the genome of the choanoflagellate Salpingoeca rosetta

Horizontal gene transfer (HGT), the movement of heritable materials between distantly related organisms, is crucial in eukaryotic evolution. However, the scale of HGT in choanoflagellates, the closest unicellular relatives of metazoans, and its possible roles in the evolution of animal multicellularity remains unexplored. We identified at least 175 candidate HGTs in the genome of the colonial choanoflagellate Salpingoeca rosetta using sequence-based tests. The majority of these were orthologous to genes in bacterial and microalgal lineages, yet displayed genomic features consistent with the rest of the S. rosetta genome-evidence of ancient acquisition events. Putative functions include enzymes involved in amino acid and carbohydrate metabolism, cell signaling, and the synthesis of extracellular matrix components. Functions of candidate HGTs may have contributed to the ability of choanoflagellates to assimilate novel metabolites, thereby supporting adaptation, survival in diverse ecological niches, and response to external cues that are possibly critical in the evolution of multicellularity in choanoflagellates.

Automated summary

Research has identified at least 175 candidate HGTs in the genome of the colonial choanoflagellate Salpingoeca rosetta, most of which are orthologous to genes in bacterial and microalgal lineages but display genomic features consistent with the rest of the genome. The functions of these potential HGTs include enzymes involved in metabolism, cell signaling, and the synthesis of extracellular matrix components. These functions may have contributed to the ability of choanoflagellates to assimilate novel metabolites and support their adaptation, survival, and response to external cues in diverse ecological niches, possibly playing a role in the evolution of multicellularity.