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

The question of the origin of the eukaryotic cell is a question of great fundamental importance. As has been stated, “basic divergence in cellular structure, which separates the bacteria and blue-green algae from all other cellular organisms, represents the greatest single evolutionary discontinuity to be found in the present-day world”.

This large question has -more or less since the discovery of asgardarchaea in metagenomic sequence data- turned into a very active research field with a lot of debate and disagreements. The contribution from Moises et al surveys an enormous amount of diverse genomes using a novel computational approach to ask the question which genes the common ancestor of eukaryotes posses and where (i.e. from which species) did they come from. This paper clearly shows that in contrast to previous models other bacteria and even perhaps viruses contributed to genes of the eukaryotic ancestor. Previous studies have sometimes considered these other potential gene donations as phylogenetic noise, i.e. the real signal is say the bacterial mitochondrial ancestor and the observed signal of that other bacterial group is just noise. But they very convincingly show these signals of other bacteria. They convincingly show multiple waves of horizontal gene transfer. 

In addition, by timing when during eukaryogenesis these genes were donated they come up with a novel scenario on how subsequent syntrophies across a microbial mat might have shaped the genome, metabolism and cell biology of the proto eukaryote. For now, this is “just a hypothesis” but unlike some other hypotheses in the field, this one is based on large scale of analysis  of genomic data. Moreover, by positing a hypothesis they guide a path forward on how to turn genomic data into syntrophy scenarios or falsify previously proposed hypotheses.