A key to the mystery of fast-evolving genes was found in ‘junk DNA’
New study turns evolutionary dogma on its head by finding that essential genes can evolve fast
![heterochromatin](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2020/11/111320_mb_heterochromatin_feat.jpg?fit=1030%2C580&ssl=1)
Heterochromatin (shown in green) was once thought of as inert "junk DNA" due to its lack of genes, but now scientists are discovering it has some very important roles.
Jose Luis Calvo/Science Source