By John Timmer, at ars technica:
Lancelet (amphioxus) genome and the origin of vertebrates
Those of you who took high school biology may remember the lancelet, also known as the amphioxus. Its simplified body plan is notable for containing a number of features that it shares in common with us vertebrates, such as a dorsal neural tube, presence of a notochord, segmented body muscles, and tail. That combination of simplicity and shared features has suggested to many that the amphioxus might shed light on the origin of the chordates. That suggestion has been dramatically confirmed by the completion of the genome of the Florida lancelet, Branchiostoma floridae, published today in Nature, with three accompanying publications that will appear later in Genome Research.
Over 500 million years ago a spineless creature on the ocean floor experienced two successive doublings in the amount of its DNA, a “mistake” that eventually triggered the evolution of humans and many other animals, says a new study: here.
Scientists reveal human worm link
Science: We’re all worms! Well, sort of. Cambridge University scientists who have traced human evolution back 500 million years have found that our species is descended from a two-inch long worm-like sea creature.
The now-extinct Pikaia gracilens is now the oldest-known member of the chordate family, which includes all modern vertebrates – including humans.
Scientists originally assumed it was related to leeches and earthworms.
But a new study published in Biological Reviews today provided the “smoking gun” that confirmed what experts had suspected – that Pikaia was the ancestor of animals with spinal cords.
http://www.morningstaronline.co.uk/news/content/view/full/116220
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