Entamoeba Clone‐Recognition Experiments: Morphometrics, Aggregative Behavior, and Cell‐Signaling Characterization

Abstract Studies on clone‐ and kin‐discrimination in protists have proliferated during the past decade. We report clone‐recognition experiments in seven Entamoeba lineages ( E. invadens IP ‐1, E. invadens VK ‐1: NS , E. terrapinae , E. moshkovskii Laredo, E. moshkovskii Snake, E. histolytica HM ‐1: IMSS and E. dispar ). First, we characterized morphometrically each clone (length, width, and cell‐surface area) and documented how they differed statistically from one another (as per single‐variable or canonical‐discriminant analyses). Second, we demonstrated that amebas themselves could discriminate self (clone) from different (themselves vs. other clones). In mix‐cell‐line cultures between closely‐related ( E .  invadens IP ‐1 vs. E. invadens VK ‐1: NS ) or distant‐phylogenetic clones ( E. terrapinae vs. E. moshkovskii Laredo), amebas consistently aggregated with same‐clone members. Third, we identified six putative cell‐signals secreted by the amebas (RasGap/Ankyrin, coronin‐ WD 40, actin, protein kinases, heat shock 70, and ubiquitin) and which known functions in Entamoeba spp. included: cell proliferation, cell adhesion, cell movement, and stress‐induced encystation. To our knowledge, this is the first multi‐clone characterization of Entamoeba spp. morphometrics, aggregative behavior, and cell‐signaling secretion in the context of clone‐recognition. Protists allow us to study cell–cell recognition from ecological and evolutionary perspectives. Modern protistan lineages can be central to studies about the origins and evolution of multicellularity.