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Title: Genotypic variability following fusion in the invasive colonial tunicate Didemnum vexillum
Abstract

Fusion to form a chimera has been documented in many marine invertebrate taxa, including poriferans, cnidarians, bryozoans, and colonial ascidians. Allogenic interactions in chimeric ascidian colonies vary widely across taxonomic groups but are poorly characterized in the invasive colonial ascidianDidemnum vexillum.The moderate level of discrimination expressed in the fusion–rejection response ofD. vexillumsuggests that there is some integration of cells beyond the fusion line in a chimeric colony. We tracked the shifts in representation of microsatellite alleles between fused colonies ofD. vexillumto elucidate the extent of genotypic integration in fused colonies and the patterns of changes to the genotypic composition of colonies immediately following chimera formation. By genotyping colonies before and after fusion, we found that allogeneic fusion inD. vexillummay lead to genotypic changes beyond the visible fusion line. Alleles from one colony were found in multiple tissue samples in the chimera 7–10 days after fusion had occurred. In some instances, alleles that were in a single colony prior to fusion were lost following fusion. We observed multiple patterns of allelic change, including both the unidirectional transfer and reciprocal exchange of alleles between fused colonies. Our findings suggest that tissue or cells are exchanged following allogeneic fusion between colonies ofD. vexillumand that the genotypic composition of chimeric colonies may be fluid.

 
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NSF-PAR ID:
10460531
Author(s) / Creator(s):
 ;  ;  
Publisher / Repository:
Wiley-Blackwell
Date Published:
Journal Name:
Invertebrate Biology
Volume:
138
Issue:
3
ISSN:
1077-8306
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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