Final answer:
Informational genes in eukaryotes likely originated from a mixture of Archaeal and Bacterial sources due to horizontal gene transfer and endosymbiotic gene fusion, with contributions from non-coding DNA adding to their complexity and functionality.
Step-by-step explanation:
The informational genes in eukaryotic cells are thought to have derived from a complex history of evolutionary processes, including horizontal gene transfer (HGT) and endosymbiotic events. Some eukaryotic genes share homology with Archaea, whereas others with Bacteria. James Lake's hypothesis involves an endosymbiotic gene fusion, suggesting eukaryotic cells emerged from a fusion between an Archaea and a Bacteria, which is supported by modern DNA analysis revealing a mix of homologies in eukaryotic genomes.
Furthermore, the presence of non-coding informational DNA such as genes for rRNAs, tRNAs, and regulatory sequences is significant in eukaryotic genomes, and they contribute to various structural and functional roles within cells.
It is also evident that eukaryotes possess genes and molecular machinery for replication and expression that appear more closely related to those found in Archaea, which continues to prompt further research and understanding in the field.