is a vestigial structure; it no longer retains its original function.]] Vestigiality describes homologous characters of organisms which have seemingly lost all or most of their original function in a species through evolution. These may take various forms such as anatomical structures, behaviors and biochemical pathways. Some of these disappear early in embryonic development, but others are retained in adulthood. Although the term serves a purpose in many gross phenotypic characteristics, vestigial has probably little applicability to DNA sequences, be they genes or non-coding sequences. The term junk DNA is a revealing example. It is a value or judgmental term which has become less utilized in genetics as many of the sequences once believed to be “junk” have been discovered to have a function. Vestigial structures are often called vestigial organs, although many of them are not actually organs. These are typically in

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