[3] Despite initial criticism and controversy surrounding his claims, Woese's three domain system, based on his work regarding the role of rRNA in the evolution of modern life, has become widely accepted.
[7] This essentially shows that the functional origin of the ribosome, responsible for protein synthesis, is common in all modern life throughout each of the three domains.
Zablen et al.’s phylogenetic analysis conducted electrophoresis on chloroplast ribosomal RNA, specifically on the 16S rRNA of Euglena gracilis.
In comparing these results, it was found that generally, these chloroplasts show a close genomic relationship, while a more distant one is seen for algae, and subsequently prokaryotic organisms.
[9] In particular, it has been proposed that ribosomes exist as a missing link in prebiotic evolution, with rRNA being a vestige of an ancient genome.
The idea of rRNA in particular being sufficient on its own to explain the progression of modern life struggles due to the fact that it lacks certain key pieces of evidence.
[13] This has also led to the proposal of other primordial molecules that may have developed into RNA and DNA, such as peptide nucleic acids, which also show evidence of self replication.