Some of the characteristics of allogeneic resorption have been revealed in studies of chimeras of two Botrylloides subpopulations (SP1 and SP3) inhabiting the Mediterranean coast of Israel. Both Botrylloides SPs exhibited the same outcomes, which differ significantly from the resorption documented in the well-studied botryllid ascidian, Botryllus schlosseri: 1. Resorption in Botrylloides chimeras was usually a very fast process starting 1 to 26 days after fusion and terminating in <9 days thereafter. 2. Resorption occurs at any blastogenic stage. 3. Resorption is complete, including zooids, buds, blood vessels and ampullae. 4. Either one of the genotypes can be resorbed in multipair chimeras of any specific combination. S. Resorption starts simultaneously in all zooids of the partner to be resorbed. 6. Time for resorption and directionality were not affected by the size ratios between the partners (0.3-1.8). As in B. schlosseri, other phenomena (disconnection, chimeric death and retreat growth) interrupt resorption in ca. 60% of the chimeras, under laboratory conditions. We propose that external stress conditions also have a significant role in a nonimmunological expression of resorption in Botrylloides.
Bibliographical noteFunding Information:
Acknowledgements--I would like to thank T. Lilker-Levav for excellent assistance during the study. This study was supported by a grant administered by the Israel Academy of Sciences and Humanities, and by a generous grant from S. Price, NAF/IOLR.
- Invertebrate immunity
- Self-nonself recognition
ASJC Scopus subject areas
- Developmental Biology