The polymorphism ofHydramicrosatellite sequences provides strain-specific signatures

Hydraare freshwater polyps widely studied for their amazing regenerative capacity, adult stem cell populations, low senescence and value as ecotoxicological marker. Many wild-type strains ofH.vulgarishave been collected worldwide and maintained effectively under laboratory conditions by asexual reproduction, while stable transgenic lines have been continuously produced since 2006. Efforts are now needed to ensure the genetic characterization of all these strains, which despite similar morphologies, show significant variability in their response to gene expression silencing procedures, pharmacological treatments or environmental conditions. Here, we established a rapid and reliable procedure at the single polyp level to produce via PCR amplification of three distinct microsatellite sequences molecular signatures that distinguish betweenHydrastrains and species. The TG-rich region of an uncharacterized gene (ms-c25145) helps to distinguish between EurasianH.vulgaris-Pallasstrains (Hm-105,Basel1,Basel2andreg-16), between Eurasian and North AmericanH.vulgarisstrains (H.carnea,AEP), and between theH.vulgarisandH.oligactisspecies. The AT-rich microsatellite sequences located in theAIPgene (Aryl Hydrocarbon Receptor Interaction Protein,ms-AIP) also differ between Eurasian and North AmericanH.vulgarisstrains. Finally, the AT-rich microsatellite located in theMyb-Like cyclin D-binding transcription factor1gene (ms-DMTF1) gene helps to distinguish certain transgenicAEPlines. This study shows that the analysis of microsatellite sequences, which is capable of tracing genomic variations between closely related lineages ofHydra, provides a sensitive and robust tool for characterizing theHydrastrains.