Subtitled “Long lambasted as junk DNA or genomic parasites, transposable elements turn out to be contributors to adaptation.”
The tale of the peppered moth (Biston betularia) is, quite literally, a textbook story of adaptive evolution. Back in the early 19th century, only one form of these now-iconic moths was known: a light variety speckled with dark spots (hence the name). In 1864, though, a naturalist in England first documented an all-dark moth—what seemed at the time to be little more than a curious example of melanin overproduction. Then came the Industrial Revolution, and dark moths took over, their inky wings reducing the odds of the nocturnal insects being eaten while they rested on soot-stained trees during the day. More than a century later, scientists discovered that the genetic tweak underscoring the moths’ dark pigmentation was a transposable element (TE).
About 200 years ago, researchers estimate, nearly 22,000 nucleotides leapt into the first intron of a moth gene called cortex, and in doing so, dramatically…Christie Wilcox, “Adapting with a Little Help from Jumping Genes” at The Scientist (January 17, 2022)
Sounds like a co-ordinated effort, actually…
Belief that most of the genome is junk is actually a philosophical position, among other things. It is hardly self-evident but for a naturalist atheist, it is something that makes sense to believe.