Nature Blog Network

Tuesday, June 17, 2008

How Did Jellies Get Human Genes? The Redux

Last year I posted on the anemone genome paper and dissuaded the creationist claim of "Where did sea anemones get human genes". Yes, I know dear reader that it actually argues for common descent. Even if phrased incorrectly.

Ed Yong, of the fabulous Not Exactly Rocket Science blog, explains new research on shared opsins, proteins involved in eye sight, between vertebrates and box jellies.

"Jellyfish may seem like simple blobs of goo, but some are surprisingly sophisticated. The box jellyfish (Tripedelia cystophora), for example, is a fast and active hunter and stalks its prey with the aid of 24 fully functioning eyes. These are grouped into four clusters called rhopalia, which lie on each side of its cube-like body. Together, they give the box jellyfish a complete 360 degree view of its world and make it highly maneuverable.

Each eye cluster, four eyes are merely pits containing light-sensitive pigments, but two are remarkably advanced and carry their own lenses, retinas and corneas. The lenses are good enough to produce images that are free of distortion and even though the views are blurrier than those we see, these complex 'camera-type' eyes are very similar to those of more advanced animals like ourselves and other vertebrates.

But these similarities extend to a more fundamental level. Even though jellyfish are the most ancient group of animals to have a well developed visual system, it turns out that their eyes are built with many of the same genetic building blocks that ours are."
Go read his post and decide if its parallel evolution or conserved.

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