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| | Dr. Stanley Shostak |
 | | In retrospect, this answer is not surprising, since asexual reproduction is a phenomenon of epithelia, while sexual reproduction is a phenomenon of amoeboid cells. |
 | | Epithelial cells alone give rise to epithelia and muscle, while amoeboid cells (also known as interstitial cells) alone give rise to cnidocytes (the sources of cnidocysts), nerve, sensory cells as well as egg and sperm. |
 | | I suggest, therefore, that epithelia and amoeboid cells in Cnidaria have separate origins: the epithelia being derived from an exclusively epithelial ancestor, possibly resembling extant Tricoplax; the amoeboid cells being derived from one or more parasitic protoctistan, possibly resembling extant members of the Microsporidia. |
| www.pitt.edu /~biohome/Dept/Frame/Faculty/shostak.htm (733 words) |
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