The Curious Case of Coral Clones. Coral embryos are naked. Unlike other animal embryos, they lack a protective capsule and float exposed in the ocean, buffeted by waves. Scientists observed that embryos at the 2, 4, 8 and 16 cell stage frequently break up into smaller clumps of cells (Image A). Does this mean that coral embryos in the open ocean are damaged and destroyed?
Surprisingly, each of these fragments goes on to become a complete larva (B) and then juvenile coral (C and D), exact clones of the original, only smaller . We call this ability totipotency: stem cells that can become any cell in the body. This unusual combination of sexual reproduction (to form an embryo) followed by asexual reproduction (to form genetic clones) has not been observed before. Those naked embryos are not so helpless after all!
REF: Science 2 March 2012: Heyward and Negri. Turbulence, Cleavage, and the Naked Embryo: A Case for Coral Clones DOI: 10.1126/science.1216055