So stretches of DNA can be copied in particular cells and then pasted elsewhere, producing a novel DNA sequence … Transpositions also occur in the brain. Fred Gage and Alysson Muotri of the Salk Institute and colleagues first showed that human transposons are activated in stem cells in the brain around the time they are becoming neurons. In other words, when you make a new neuron, that old boring DNA sequence that you inherited isn’t good enough. Thus, the brain is a mosaic of neurons with different DNA sequences. “Genes Often Get Shuffled in Our DNA Deck,” by Robert M. Sapolsky
I don’t know what this means, but it is absolutely fascinating. As the article mentions, the vast, vast majority of snowmobiles don’t work, but a vital few do. Plants are especially good at this game, and bacteria, the most successful life form on the planet — you are, basically, just a life support mechanism for a bunch of bacteria — are masters.