"Vertebrates emerged around 500 million years ago from a massive evolutionary upheaval at the bottom of the ocean that involved two successive doublings in the amount of DNA in a marine invertebrate. These dramatic events triggered the evolution of a new animal, which became the ancestor of the backboned fishes, birds, reptiles and mammals, including humans. These ancient DNA doublings boosted internal communication systems. The downside is that communication breakdowns cause diabetes, cancer and neurological disorders. You can still see the "family resemblance" between amphioxus and humans, because it has a nerve cord running down its back, blocks of muscle, and branchial arches where we have facial structures. However, amphioxus has no bones, no brain, no face and no heart. It is because of the two genome duplications that we gained the complexity to develop all these features." http://rsob.royalsocietypublis... - Adriano

We are all originally pond scum. - Eric Logan

Amphioxus embryonic development from fertilization to mid-neurula: http://youtu.be/ycHJMXUT2o0 by Alain Camasses and Hector Escriva at Laboratoire Arago, Banyuls sur Mer, France. \\ « Au moment de notre conception, nous sommes une simple boule. » - Adriano

There's prior research from 2008 (much more readable) estimating the evolutionary distance ~520 million years: "The amphioxus genome illuminates vertebrate origins and cephalochordate biology" Genome Res. 18(7):1100–1111, http://www.ncbi.nlm.nih.gov/pmc... - Adriano