Reacción a "A Spanish study published in Nature reimagines the origin of our cells as a story of microbial alliances"

Gabaldón's group has published a robust study, using a large amount of data and advanced phylogenomic methods, that allows for the reconstruction of the proteome of the last common ancestor of eukaryotes (LECA), as well as the analysis of the contributions of other lineages to its chimeric genome.

Beyond the contributions of the two widely recognized partners in the origin of the eukaryotic cell (an archaeon ancestral to modern Asgard bacteria and an alpha-proteobacterium, the precursor of mitochondria), there must have been many other horizontal gene transfers from bacteria and viruses along the path of LECA genome construction. The authors identify at least two waves of gene transfer to the archaeal host, prior to the emergence of mitochondria.

Furthermore, this study offers hypotheses about the ecological context of the microbial mats in which these encounters, resulting in eukaryotic complexity, must have occurred.

The contributions of Gabaldón and his colleagues reinforce the idea that eukaryogenesis followed a genetically hybrid evolutionary mode (much more complex than the binary archaea-bacteria encounter) marked by a prolonged timescale, consistent with their earlier ideas about a late origin of mitochondria.