Repetitive Sequences Don't Imply Junk DNA
It seems like part of the argument in favor of junk DNA is the various types of repetitive sequences found in DNA. Shouldn’t repetition imply design instead? I don’t know anything about electronics but I do know what I see when I pop the cover off my computer and look at the circuit boards – the same old widgets used over and over again.
Consider software. If you look at software executables (like .exe and .dll files on Windows computers) they are full of repeated sequences. You may have written a program yourself. If so, you would certainly be familiar with the concept of a subroutine. At the assembly level, whenever a subroutine is called registers are pushed on the stack, when one returns they are popped of the stack. The code to push and pop registers is automatically generated by the complier and is therefore not apparent at the source code level. This translates into a massive amount of simplistic repetition at the binary level. These kinds of repetitive sequences would probably be classified as SINES by geneticists trying to understand the binary code. While this kind of code doesn’t map to any kind of a program function it is essential.
You may also know that most software developers these days work with object oriented languages where inheritance and polymorphism are used to develop hierarchies of classes. At the source code level inheritance enables developers to reuse source code without retyping it. However, when source code is compiled into binary form the result is a massive amount of repetition, but of a more sophisticated nature than that of just pushing and popping registers. These kinds of repetitive sequences would probably be classified as LINES.
You could say that repetition is a sign of information. Aflkjkjnejiadudfmoqe. The characters preceding this sentence were randomly typed and contain no information. This sentence repeats character sequences that have been used before and you can recognize them. The repetitive nature of DNA implies information content – not the other way around.