Much of so-called junk DNA is in non-coding regions that are not within introns. For example, there are long regions containing just repetitive viral DNA sequences with no coding DNA anywhere; this is often what people mean when they say junk DNA. But those regions aren't intronic, because they are not spliced out of the preprocessed mRNAs.
Much of so-called junk DNA is in non-coding regions that are not within introns. For example, there are long regions containing just repetitive viral DNA sequences with no coding DNA anywhere; this is often what people mean when they say junk DNA. But those regions aren't intronic, because they are not spliced out of the preprocessed mRNAs.