Ctenophores look like small mirror-faced balls, using specialized body hair to propel themselves around the ocean and lick small prey with sticky tentacles. "They're aliens who came to Earth," said Leonard Moroz, a neuroscientist at the University of Florida by Augustine.
Ctenophores lack many common genes
Recently, nature reported the genome of Moroz and his team pleurobrachia bachei, adding to the mystery of ctenophores. The sequence omits the types of genes found in all other animals, including normal genes related to immunity, development, and neurological function. In response to this situation, the researchers discussed that ctenophores evolved a separate nervous system.
Ctenophores have long plagued taxonomists. Their similarity to jellyfish causes them to occupy a seat on the tree of life as sister groups of coelenterates (this phylum includes jellyfish). On the basis of their nervous system, which is able to perceive light, perceive prey and move muscle tissue, many researchers branch them off from the common ancestor of other animals, sponges and flat multicellular clumps called flat discs, which do not have a nervous system. Available data suggest that ctenophores lack blood-like genes, and some scientists argue that they are the closest living relatives of the first animal.
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