

Previously it was thought that non-coding sequences were junk, and enormous numbers like 99% were thrown around at the time. Later, we found out that more and more of the non-coding regions actually do various other things, and the scope of junk DNA got narrower as years went by. Nowadays, you don’t really hear that term much, because future scientists have a tendency of discovering new functions for sequences that were previously thought of as non-functional. There’s also debate as to where do we draw the line.
As usual, biochemistry is a fast moving target, and people have gotten cautious about these things. As more and more is discovered, older notions are updated or even thrown away.
I’ve read some stories of someone transmuting Ubuntu into Debian or something like that. It requires lots of knowledge of both systems, plenty of time, and infinite patience. The two distributions should be somewhat closely related in order to make this gargantuan project even remotely feasible. If you’re jumping from Arch to Gentoo, you might as well just do LFS while you’re at it.