Designers don’t make junk. The use of the term “junk DNA” conveyed to the public that much of the human genome was useless sequences left over from a long process of evolutionary trial and error. But the term junk has now been found to be inappropriate. Thus the evolutionary connection has now disappeared as well.
The entire sequence of DNA in each human cell is over 3 billion nucleotides long. About 1-2% of these nucleotides are involved in coding for genes. By definition, each gene codes for one protein. The rest of the DNA is called non-coding. Initially scientists had no idea whether all this DNA had any function of not. With few ideas as to what any function might be, scientists assumed that it had no function and was actually left over debris from evolution. Thus non-coding DNA was called “junk DNA”. But recent studies have revealed an amazing variety of functions in the non-coding DNA. So junk DNA is a failed evolutionary concept.