Humans could regrow limbs as scientists uncover a 'DNA switch' – Daily Mail


Humans of the future could REGROW limbs! ‘DNA switch’ that controls genes for regeneration used by worms to grow back their bodies after being cut in half is discovered

  • Scientists have discovered that non-coding or ‘junk’ DNA controls regeneratio
  • Full-body regeneration is seen in jellyfish, sea anemones, and planarian worms 
  • ‘Junk’ DNA controls the activation of a gene called early growth response (EGR)
  • Humans have EGR to repair cells but it doesn’t trigger large scale regeneration
  • Researchers are now trying to change the gene so that we too can ‘regenerate’

People could one day have the ability to grow back parts of their bodies after a ‘DNA switch’ that could reactivate the genes that control regeneration were found.

Animals like salamanders and geckos can shed parts of their bodies to escape predators and grow new ones that have been cut off in just a couple of months.

Planarian worms and jellyfish go one step further by regenerating their whole bodies after being cut in half.

Now a team of scientists have examined genes of three-banded panther worms to shed light on how they accomplish this.

They found that a ‘master’ control gene called early growth response (EGR), which is also found in humans and other animals, is responsible.

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Scientists have uncovered a DNA switch that could give humans the ability to grow back their limbs. Animals like salamanders or geckos can shed parts of their bodies to escape predators and form new parts. The study examined the genetic switches in three-banded panther worms

Scientists have uncovered a DNA switch that could give humans the ability to grow back their limbs. Animals like salamanders or geckos can shed parts of their bodies to escape predators and form new parts. The study examined the genetic switches in three-banded panther worms

Researchers from Harvard University discovered that a section of non-coding DNA – controversially labelled by some as ‘junk’ DNA – controls the activation of EGR which acts like a power switch for the regeneration process.

Non-coding sections of DNA are not directly involved in the process of creating the proteins that trigger a whole host of biological processes.

This led some to believe that these sections of our genes and those of other animals serve no useful purpose.

More recent research has suggested that the picture is far more complicated, including Harvard’s study.  

Humans already have the EGR ‘switch’ that repairs cells yet it does not seem to trigger large scale regeneration.

Scientists now think that the gene is wired differently in humans and are now trying to find a way to change this to reap so that we too can ‘regenerate’. 

‘What we found is that this one master gene comes on…and that’s activating genes that are turning on during regeneration,’ said Dr Andrew Gehrke, a post-doctoral fellow at Harvard and lead author on the study. 

‘Basically, what’s going on is the non-coding regions are telling the coding regions to turn on or off, so a good way to think of it is as though they are switches.’ 

Animals like salamanders or geckos can shed parts of their bodies to escape predators and form new parts in just a couple of months. Planarian worms and jellyfish, here, can go one step further by regenerating their whole bodies after being cut in half

Animals like salamanders or geckos can shed parts of their bodies to escape predators and form new parts in just a couple of months. Planarian worms and jellyfish, here, can go one step further by regenerating their whole bodies after being cut in half

WHAT CAUSES SPECIES TO REGENERATE?

All organisms, including humans, have the ability to regenerate to a degree, but the process is much more developed in many invertebrates such as earthworms and starfish. 

These animals can grow new heads, tails and other body parts when injured.

Scientists don’t know why mammals don’t have the same ability, but they do regenerate skin, muscle and blood. 

Every multicellular organism is built from a single cell, which divides into two identical cells, then four, and so on.

Each of these cells contains the exact same twisted strands of DNA, and is considered pluripotent – meaning it can give rise to all possible cell types in the body.

But somewhere along the way, those starter cells – known as embryonic stem cells – resign themselves to a different fate and become skin cells, heart cells, muscle cells, or another cell type.

For that process to work the DNA in the worms’ cells, which is normally tightly folded and compacted, has to change, making new areas available for activation. 

Portions of these very tightly packed portions of the genome – the full genetic code of the worms studied – physically become more open, experts say.

They act as regulatory switches to turn genes on or off, suggesting their genomes is dynamic and rapidly changing, as different parts open and close.

While the study reveals new information about how the process works in worms, it also may help explain why it doesn’t work in humans. 

Dr Mansi Srivastava, an assistant professor of organismic and evolutionary biology who led the study, said: ‘The question is: If humans can turn on EGR, and not only turn it on, but do it when our cells are injured, why can’t we regenerate?’ 

‘The answer may be that if EGR is the power switch, we think the wiring is different. 

‘What EGR is talking to in human cells may be different than what it is talking to in the three-banded panther worm.

‘What Andrew has done with this study is come up with a way to get at this wiring. 

‘So we want to figure out what those connections are, and then apply that to other animals, including vertebrates that can only do more limited regeneration.’

The full findings of the study were published in Science



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