[adrotate banner=”1″]Junk DNA seems to have every explanation on the planet for what it is for. And they are all wrong. Everyone knows Junk DNA is really spare parts carried in case DNA Vampires from the planet Neptune attack the Earth again. That way, you have spare DNA to keep yourself alive long enough to defeat them yet again. The explosive addition of microRNAs talked about in this article is just the result of one such DNA Vampire attack and the explosive growth in DNA diversity that follows after the vampires’ defeat.
ScienceDaily (Feb. 12, 2008) Dartmouth College researchers and colleagues from the University of Bristol in the U.K. have traced the beginnings of complex life, i.e. vertebrates, to microRNA, sometimes referred to as ‘junk DNA.’ The researchers argue that the evolution of microRNAs, which regulate gene expression, are behind the origin of early vertebrates.
Vertebrates – animals such as humans that possess a backbone – are the most anatomically and genetically complex of all organisms, but explaining how they achieved this complexity has vexed scientists since the conception of evolutionary theory.
The team studied the genomics of primitive living fishes, such as sharks and lampreys, and their spineless relatives, like the sea squirt. By reconstructing the acquisition history of microRNAs shared between human and mice, the researchers determined that the highest rate of microRNA innovation in the vertebrate lineage occurred before the divergence between the living jawless fishes like the lamprey and the jawed fishes like the shark, but after the divergence of vertebrates from their invertebrate chordate relatives, such as the sea squirt.
Alysha Heimberg of Dartmouth College and her colleagues showed that microRNAs, a class of tiny molecules only recently discovered residing within what has usually been considered ‘junk DNA’, are hugely diverse in even the most lowly of vertebrates, but relatively few are found in the genomes of our invertebrate relatives.
She explained: “There was an explosive increase in the number of new microRNAs added to the genome of vertebrates and this is unparalleled in evolutionary history.”