  Gene skeptics such as Burian, Portin, and Fogle claim that the term gene has outlived its usefulness. They argue that the term is both too vague and too restrictive. It is too vague, they believe, because it does not provide a unique parsing of the genome. Borders between genes are overlapping and allegedly ambiguous. It is not clear, they argue, whether genes include or exclude introns, regulatory regions, and so forth. The term is allegedly too restrictive because it obscures the diversity of molecular elements playing different roles in the expression and regulation of DNA. In addition, any attempt to resolve the ambiguities, these skeptics argue, will make the term even more restrictive.