Junk DNA is a myth
Probably one of the most absurd scientific ideas that I have ever read about is the idea that approximately 97% of human DNA is junk. Wikipedia (June 26, 2007) says that:
"About 97% of the human genome has been designated as "junk", including most sequences within introns and most intergenic DNA. While much of this sequence may be an evolutionary artifact that serves no present-day purpose, some is believed to function in ways that are not currently understood. Moreover, the conservation of some junk DNA over many millions of years of evolution may imply an essential function."
It's hard for me to believe that any thoughtful person could believe such an absurd theory. On what authority do I make such a claim? Well, not much. I am not a geneticist or a molecular biologist. In fact, I only read a couple of books on genetics. However, as a software developer I have a vague idea of how many bytes of code are needed to make complex software programs and I am amazed that something as complicated as a human being is encoded in as little as 3.2 billion base pairs of DNA.
To be more specific, since the DNA alphabet consists of 4 nucleobases, we can represent a nucleobase with 2 bits data. This means that 4 base pairs can be represented by a byte of data and approximately 4 million base pairs can be represented by a megabyte of data. This means that the entire human genome can be represented by only 800MB of code. From my 25+ years of experience as a software developer, this would have to be highly efficient code. To suggest that 97% of DNA is junk implies the implausible -- that only 24MB of DNA is not junk. By comparison, the Microsoft Word executable has a size of 12MB which is half as much information (and that doesn't even count all the DLLs and operating system code that it relies on).
I think it's more probable that we haven't yet discovered all of the biological information required to produce humans and other forms of life.
What about repetitive DNA sequences?