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From: The Proceddings of the National Academy of Science (PNAS) > Research Article
Comparative genomics of mortal and immortal cnidarians unveils novel keys behind rejuvenation
Maria Pascual-Torner, Dido Carrero, José G. Pérez-Silva, et.al.
Edited by Vera Gorbunova, University of Rochester; received October 13, 2021; accepted July 6, 2022 by Editorial Board Member Helen M. Blau
August 29, 2022
119 (36) e2118763119 ...
Abstract
Turritopsis dohrnii is the only metazoan able to rejuvenate repeatedly after its medusae reproduce, hinting at biological immortality and challenging our understanding of aging. We present and compare whole-genome assemblies of T. dohrnii and the nonimmortal Turritopsis rubra using automatic and manual annotations, together with the transcriptome of life cycle reversal (LCR) process of T. dohrnii. We have identified variants and expansions of genes associated with replication, DNA repair, telomere maintenance, redox environment, stem cell population, and intercellular communication. ... Accordingly, we propose these factors as key elements in the ability of T. dohrnii to undergo rejuvenation. ...
Only three species within the genera Turritopsis have been reported to rejuvenate after reproduction: Turritopsis dohrnii, Turritopsis sp.5, and Turritopsis sp.2 (9). However, while the latter two sharply drop their reversal capacity after reaching maturity, T. dohrnii is the only one that maintains its high rejuvenation potential (up to 100%) in postreproductive stages, reaching biological immortality (10, 11). ...
In this study, we have sequenced the genomes of T. dohrnii and T. rubra, a closely related species without reported evidence of postreproductive rejuvenation (9) (Fig. 1), and used comparative genomic analyses to identify differential gene variants and amplifications between both species ... .
CAPTION: Geographical origin and life cycle diagram of T. rubra (Left) and T. dohrnii (Right). Light blue arrows indicate the typical life cycle while dark blue indicates the alternative ontogeny reversal of T. dohrnii. In this process, the free swimming medusa shrinks until the cyst stage, where all structures from the medusa totally disappear into a homogeneous opaque mass. Later, a stolon starts growing from the cyst and polyp buds appear to become fully grown polyps afterward.
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