Inquiry
How did Lavos absorb DNA?
Answer
One probable method:
Lavos used the earth's life forms as experimental test subjects. Lavos' genetic manipulations had a dual purpose: 1.) discover new, superior genetic traits and 2.) determine how to incorporate these traits into its genetic code. Lavos did not have the ability to invent new genetic traits from scratch. If Lavos knew of a superior trait, and how to insert that trait into a species' genome, it would simply insert the gene into itself. Only by observing the evolution of the earth's lifeforms could Lavos improve its own fitness.
Lavos would have inserted genes coding for traits it already possessed, or knew of from its past travels, into the earths lifeforms. This would involve inserting DNA sequences into cells at random, most likely requiring many attempts before producing viable results. Over time, random genetic mutation and natural selection would produce new, improved variants of that trait. But, after identifying a beneficial trait, it is very difficult, if not impossible, to determine exactly what combination of genes are responsible for it. Lavos would have to maintain a control group without any genetic modification, so it could compare the genomes of similar species, and identify the key genes.
For example, take the ability to use magic in humans. Lavos took a trait which it already possessed, and transfered it to humans by inserting parts of its own DNA into the human genome. The control group, with no genetic modifications, are the Earthbound ones. The modified humans carrying Lavos' initial genetic modifications would comprise the Enlightened ones. Their ability to use magic is a recessive trait. The humans who had evolved beyond Lavos' original genetic trait would be the innate magic users, such as the Zealian Royal family. It is their DNA which Lavos would incorporate into its own genome. All the improvements in turn are passed on to the Lavos spawns.
This also presents the possibility that all life on earth contains some of Lavos' DNA. Now that is a disturbing thought.