‘Biologically immortal’ creature named hydra can grow new heads at will

By Tom Campbell via SWNS

Immortal water creatures can sprout new heads by tweaking their genes, reveals a new study.

Hydra have the ability to regrow their body parts by turning the right genes on and off at the right time, according to a new study.

The small group of aquatic creatures, which live in temperate and tropical regions, are commonly believed to be "biologically immortal" as they can constantly repair themselves.

While whole-body regeneration has been observed in some animals before, the genetic processes vary across species and remain largely unexplored.

Now scientists at the University of California Irvine have mapped out the hydra's genetic secrets.

Lead author Dr. Aide Macias-Muñoz said: "One exciting finding of this work is that the head regeneration and budding programs in hydra are quite different.

"Even though the result is the same (a hydra head), gene expression is much more variable during regeneration."

Hydra, which can cling to surfaces or glide through the water, are one of around 10,000 species belonging to a group of animals known as Cnidaria.

They come all different colors and resemble a floating dandelion seed with two distinct body parts, including a head and foot.

The researchers identified 27,137 elements in one or more sections of the hydra's body or regenerating tissue.

They then used a scientific method known as histone modification ChIP-seq, to analyze how proteins interacted with DNA.

More than 13,000 pieces of DNA which could be bound by protein and copied through a process known as transcription, were identified by the researchers. ​

A number of these elements changed while the hydra's head grew back, according to the researchers.

These changes could govern the organism's regeneration process by turning on or off certain genes depending on its needs.

As hydra do not appear to die of old age, their regenerative abilities have become especially interesting to biologists around the world.

When cut in half, each part will regenerate and form into a new small hydra, with the head becoming the foot and vice versa.

If the hydra is sliced into many segments, then the middle slices will form both a head and a foot.

When alarmed or attacked, the hydra tentacles can be retracted to small buds and the body to a small gelatinous sphere.

They feed on many tiny animals, including worms, small crustaceans, baby fish, young insects and larval mollusks

Dr. Macias-Muñoz said: "Accompanying dynamic gene expression is dynamic chromatin remodeling at sites where developmental transcription factors bind.

"These findings suggest that complex developmental enhancers were present before the Cnidaria and Bilateria split.”

The findings were published in the journal Genome Biology and Evolution.