Efficient dispersal and substrate acquisition traits in a marine invasive species via transient chimerism and colony mobility

• DOI: 10.7717/peerj.5006
• Publication Date: 2018-06-15T10:38:01Z
• Authors: Andrew E. Fidler; Aurelie Bacq-Labr...; Elad Rachmilovitz; Baruch Rinkevich
• Keywords: Zooid; Chimera (genetics)

Over the past three decades colonial ascidian Didemnum vexillum has been expanding its global range, significantly impacting marine habitats and aquaculture facilities. What biological features make D. so highly invasive? Here, we show that juxtaposed allogeneic colony fragments (‘ramets’) may, initially, form chimeric entities. Subsequently, zooids of differing genotypes within such chimeras coordinately retreat away from fusion zones. A few days following post-fusion movements there is further ramet fission formation zooid-depauperate tunic Using polymorphic microsatellite loci to distinguish between genotypes, found they were sectorial at zones subsequent resulted in spatial separation paired-genotypes indicating events observed did not lead long-term, stable chimeras. Thus, ramets initial progressive segregation probably minimizing potential somatic/germ-cell competition/parasitism. We speculate relatively fast (≤10 mm/day) movement colonies on substrates along with frequent, perhaps unrestrained, transient fusions play significant roles this species’ striking invasiveness capacity colonize new substrates.