Why should Hydra be a model organism for aging research?

Description of Hydra:

  • small (~1-3mm)
  • solitary
  • cnidarian polyps
  • live in freshwater pools and streams
  • 16 species in North America
  • simplest of multicellular animals

Physiological Traits:

  • consist of stalk with gastric cavity and tentacles around opening
  • two germ layers: ectoderm and endoderm; acellular mesoglea in between
  • lack traditional organs, but do have diffuse nervous system
  • asexual reproduction and sexual reproduction under certain conditions
  • stem cell lineages that result in unlimited regenerative capability (restore after disaggregated)

This organism is poised for more extensive development for aging research.

Sex Related Aging

Hydra vulgaris has been shown to lack senescence even with a declining reproductive rate. Other Hydra species do show increasing mortality with age when induced to undergo sexual differentiation. this includes deterioration in physiological functions. Aging and its absence can be observed in the same species.

Recent Experiments

  • Hydra magnipapillata’s genome has been sequenced.
  • Transgenic animals have been produced expressing green fluorescent protein by injecting plasmids into oocytes.
  • Gene silencing by fedding with bacteria produced double-stranded RNA (dsRNA) has be used.

Genome Database for Hydra

Sequenced Hydra magnipapillata. Provides the use of BLAST to search genome and proteome.



Austad, S. N. (2009). “Is There a Role for New Invertebrate Models for Aging Research?” Journals of Gerontology Series a-Biological Sciences and Medical Sciences 64(2): 192-194.

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