In this blog, there are numerous references regarding hierarchical endosymbiosis. Simply put, this phrase means that cells swallowed smaller cells that were, in turn, swallowed by larger cells and so forth. Not only did this swallowing happen, but the genetic material of the swallowed cells was retained and utilized by the host cell.
What evidence is there for such a phenomenon in nature? For starters, it has been pretty much universally accepted that endosymbiosis created cells such as we have now, called eukaryotic cells. In animals and fungi, it involved swallowing an oxygen utilizing bacterium called a mitochondrion. This is why we need oxygen to survive. In plants, it also included an extra bacterium called a cyanobacterium, one involved with photosynthesis. However, endosymbiosis can go even further than this to include secondary and even tertiary endosymbiosis. Based upon this knowledge, there is no reason such hierarchical endosymbiotic events could not have been a driving force for eons, leading to cells with huge amounts of DNA such as our own, incorporated from alien sources. You can learn more about hierarchical endosymbiosis and its impact on chromosome structure, embryology, cancer, and rapid evolution by perusing this blog or asking me questions via e mail at email@example.com or by posting comments.