Answer:
By phylogenetic analyses
Explanation:
The target of rapamycin (TOR) is a major regulator of growth only found in eukaryotic organisms. The TOR pathway is known to regulate critical cellular processes including, among others, cell growth. The TOR protein is a kinase capable of activating translation by phosphorylation of the ribosomal S6 kinase (S6K) and the eukaryotic translation initiation factor 4E binding protein (4E-BP). In this regard, phylogenetic studies have shown that this pathway involves duplication events of ancestral kinases, as well as sub-functionalization of the S6K kinase.
