In Greek mythology, a hydra was a gigantic snake that had several heads (the number could vary, since it was not a fixed number), and that blew poisoned breath through its mouth over the marshes of Lerna, near Argos .
The destruction of the Hydra was one of the twelve labors of Hercules, who accomplished it with the help of his nephew Lolaos. In fact, the story goes that when one head was cut off, suddenly two would appear. Because of this, the character was forced to burn each monster’s wound with fire, eventually ending up with him severing the head out of the way (which was sometimes said to be immortal).
As we see, although in Greek mythology, the hydra is a large serpent with many heads , in our world today, the hydra consists of a small freshwater polyp , an amazing creature, with an incredible reputation: it tends to be virtually impossible to kill.
Due to this, scientists have been studying it for years, trying to understand what would be the mechanism of immortality of this small animal, with incredible capacities to regenerate. Not surprisingly, the hydra can re-regenerate the parts of its body that would have been amputated . And not only that: from these detached or amputated parts, a new animal can even develop.
The hydra consists of a multicellular organism , a tubular cylinder with a pedestrian appendage located at one end, and a tentacle-shaped mouth at the other. Previously, some aspects related to hydra regeneration have been identified, but scientists wanted to understand how its genome directs its cells to develop a completely new head.
Thus, a study published earlier this month in Genome Biology and Evolution would help shed more light on it.
The research was carried out in the Mortazavi laboratory of the University of Irvine, specifically in the Department of Developmental Biology and Cell Biology.
According to their authors, “scientists have known that hydras can regenerate since they discovered these small animals about 280 years ago.”
To further investigate them, “the researchers first identified more than 27,000 genetic factors that play a role in hydra regeneration, then mapped smaller subsets of several thousand elements to find the switches in the hydra genome that were only present. active when hydras produced new shoots ”.
They thus discovered that when a hydra sprouts, it takes around 72 hours for a bud to grow back, while a bud to regenerate . The replacement, finally, takes about 48 hours.
According to the scientists, “during budding, genes (including those involved in the main organizer) appear to increase slowly and steadily over time.” While, “during regeneration, however, genes have more dynamic expressions, some increase rapidly and then decrease, and have a peak of expression at different times of regeneration.”
For the first time, researchers have observed variations in the genetic instructions for head growth in hydras , such that hundreds of different genes are at work in the three processes of a new head’s growth, its development, and eventually its subsequent outbreak.
In other words, “this would mean that there are three different ways for the hydra to make a head, depending on the circumstances.”
