Answer in no more than 500 words.
Chordates are characterized by having a dorsal hollow nerve chord,
a notochord, and a tail. Some years ago, researchers discovered
that in Tunicates, a single mutation in one gene caused the nerve
chord, the notochord, and the tail to all disappear. A writer for
Science magazine concluded from this that all three definitive
chordate traits must have evolved at the same time, with the
appearance of this gene. Explain the flaw in this...