Hydra is the name of a many-headed water beast in Greek Mythology…but it’s a real animal too!
- Hydra is a cnidarian
- It is exclusively a freshwater organism
- There are many different species of Hydra
- It is relatively small, being only a half a centimeter long on average
- Hydra have a tubular body, a “head” at the distal end, and a “foot” at the proximal end
- They use this foot for sticking to either rocks or the undersides of plants
- They have a ring of tentacles for catching food around the head
- Hydra only has ectoderm and endoderm (no mesoderm!)
Reproduction and Life Cycle:
- Hydras generally reproduce asexually
- They do this through budding
- If the environmental conditions get bad enough, they are likely to switch to sexual reproduction, which increases the genetic variation in the population.
Why Study Hydra?
- Regeneration – Hydra can regrow a lost head or foot, or both!
- Senescence – Hydra do not show any signs of senescence (the process of aging) as long as they reproduce asexually. Studying Hydra‘s “immortality” may help in research on geriatric medicine. Interested in how Hydra could help with Alzheimer’s disease and Huntington’s disease? Read about it here.
- Stem cells – Hydras present a simple, non-controversial method for stem cell research. Common signaling pathways are responsible for stem cell functions in Hydra and humans. Read more about Hydra stem cells in this article by Thomas Bosch.
- Read here about advancements in discovering the pathways involved in Wnt3, “the master ligand”, signaling. HyWnt3 expression begins the cascade for Hydra head regeneration, controlled by two cis regulatory elements: HyWnt3act and HyWnt3rep.
Read more about Hydra from Encyclopedia Britannica