Genomic studies and many hypotheses suggest that all living
organisms on Earth have a common descent and that common ancestor
is LUCA. In a recent study done by comparing the genomic DNA of
many living organisms, it has been found that almost around 350
genes found in present day organisms are common to the genes found
in LUCA. These hypotheses suggest the presence of LUCA and that it
is the common ancestor to Bacteria, Archea and Eukaryota, and this
evolutionary process took place with the help of Horizontal gene
Transfer. Hence, we can conclude that the first eukaryotic cell
arose from within the lineage of last universal common ancestor
(LUCA).