Ascidian one-half embryos can develop into functional adult ascidians.
Although adult ascidians have remarkable regenerative potency, the ascidian egg is considered a typical "mosaic" egg. A single blastomere isolated at the two-cell stage develops into a half tadpole with minor or major defects, and this rigidity of ascidian development is known to depend on the localization of cytoplasmic determinants. Between the egg and adult, the ascidian larva has a dual nature consisting of differentiated cells for larval activities and undifferentiated cells that later become differentiated and function in the adult. Although ascidian larvae derived from a hemiembryo are deficient, no one has yet investigated the possibility that the adult might have regulative powers not present in the embryo and might be able to form an entire adult ascidian. Using Styela plicata, we have approached this problem. We report here for the first time that ascidian half embryos can form tadpoles that have the potency to hatch, metamorphose, and develop into functional ascidians.
D000818:Animals; D002454:Cell Differentiation; D005786:Gene Expression Regulation; D007814:Larva; D008675:Metamorphosis, Biological; D014561:Urochordata / Q000196:embryology*