But it is true that huge amounts of our genome don't do anything. There are sequences where the same letter or string repeats thousands of times. There are many copies of things that have accumulated mutations that make them non-functional.

The idea that repeated sequences in certain genomes are non-functional or 'junk' is questionable, as they provide additional encapsulation to chromosomes with cell nuclei (a sort of fault tolerance).[0]

[0]: https://www.sciencedirect.com/science/article/pii/S108495212...

Computer architectures sometimes necessitate no-ops under certain circumstances to facilitate functionality. Even though they're no-ops, they're not useless. To the contrary, they have very specific and required uses, which is why they exist.

Evolution works on integrated systems, not parts. Which goes a long way toward explaining why life doesn't seem to have any single-use components - everything serves multiple purposes. We just don't understand them all yet.

That hasn't changed. It's still ~90% junk.

  Total Essential/Functional (so far) = 8.7%
  Total Junk (so far) = 65%
  Unknown (probably mostly junk) = 26.3%

  https://sandwalk.blogspot.com/2011/05/whats-in-your-genome.html
  https://sandwalk.blogspot.com/2008/02/theme-genomes-junk-dna.html

There's a reason for everything.

There is a reason for all the junk in my drawer, but it is still junk.

In cases like this why don’t they try grow a fern that only has genes with an identified purpose and go from there?