vestige

n. sign, mark, trace; remnant; undeveloped remains of a body part or an organ that was healthy and functional in a previous stage of development (Biology)

In evolutionary biology and comparative anatomy, vestigiality is a term which describes homologous characters of organisms which have 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. All such characters can in turn can be traced to the genes which code for such characters. Some genes no longer code for anything, and can thus be said vestigial themselves, or junk DNA.
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Noun
1. an indication that something has been present; "there wasn't a trace of evidence for the claim"; "a tincture of condescension"
(synonym) trace, tincture, shadow
(hypernym) indication, indicant
(hyponym) footprint

n. vestige, survival; relic, trace, mark

(n.)
The mark of the foot left on the earth; a track or footstep; a trace; a sign; hence, a faint mark or visible sign left by something which is lost, or has perished, or is no longer present; remains; as, the vestiges of ancient magnificence in Palmyra; vestiges of former population.