The Biology of Claire Bennet: Wait how many mutations was that?

Note: this was originally posted on my blog on tumblr.com. I have tried to convert some of the formatting over, however there may be some inconsistencies. Also this particular entry was written before I knew how to cite scientific sources, so sources will either be nonexistent or incorrectly cited. 

In the TV show Heroes Claire Bennet has the ability to heal, and later has the ability not to feel pain. She survived falling from great heights, car accidents, and extreme levels of radiation. All in the first season. But how does her ability function on a biological level?

Claire initially just has the ability of heal, so let’s look at that first.  Any cuts or scrapes that Claire sustains are quickly healed without any scaring. She can also regenerate limbs, or at least small ones like toes. This ability is a lot like one that some lizards have. If the tail or the leg of certain types of lizards is cut off they will grow back the lost appendage. They do this by having a bunch of undifferentiated cells (cells that haven’t been told that they are going to do. They haven’t been given a job, like being a skin cell) and the limb rebuilds its self. The genes that in lizards that allow them to regenerate like this turn out to actually be in most vertebrates including humans.

Then why aren’t we all Claire Bennet?

In humans, before the undifferentiated cells can be made, the immune system kicks in. It inflames the area and the body patches up the wound with a nice scab. This works really well if you want to keep harmful microbes out of the wound, however it also keeps the undifferentiated cells from going in and filling in the wound. So Claire is likely able to regenerate by delaying her clotting system and letting the undifferentiated cells do their thing. Somehow she is able to rapidly regenerate the tissue (in lizards it can take days or weeks to regenerate but Claire’s toe grows back in less than a minute) before clotting even begins.

Claire’s ability is also very similar to that of lizards in another way. In experiments where scientists damaged the nerves around the wounded tissue the tissue did not regenerate. This means that the ability to regenerate is somehow linked to the nervous system, and the brain. Why there is a connection or how it works isn’t well understood, but there is one. This explains why Sylar is able to look at Claire’s brain and take her ability, however he never develops her ability not to feel pain. Her ability to feel pain wouldn’t be apparent by looking at her brain structure and there for Sylar only got the ability to heal.

Claire’s inability to feel pain begins after Sylar cuts open her head. Why the sudden change? Well the event was obviously traumatic, he did open her skull and then put it back together again.  Her body likely responded to try to balance things out. There is something that has just cut open your skull and put you through extreme pain. You’re still alive because your body can regenerate but that is more pain than someone should be able to experience and still be alive. So her body likely changed her gene expression, turning on new genes that would prevent the brain from receiving the pain signals.

There are actual people who can’t feel pain, the disorder that seems to fit the best is congenital insensitivity to pain. Congenital insensitivity to pain has been seen in three different mutations, but all three prevent the pain signals from being sent down the neuron. The reason why this disorder works the best for Claire is that there are very few side effects other than the lack of feeling pain. People with the mutations can still feel pressure and temperature changes, which is something that someone with nerve damage would not be able to do. However congenital insensitivity to pain is always expressed from childhood. So either Claire had it from birth, which seems unlikely, or it’s linked to the mutation that causes her ability. When she manifested her ability the mutation that prevented pain also turned on, however for whatever reason there was a delayed reaction until the trauma of Sylar cutting open her head.

So not only does Claire have a mutation that allows her to have an ability in the first place, she also has a completely separate mutation that allows her not to feel pain. On top of this she is likely to have a mutation in her DNA structure. The character Adam Monroe has a power very similar to Claire, he can heal, and he is several hundred years old and hasn’t aged a day over that time. It is safe to assume that Claire also is immune to ageing. It’s thought that ageing occurs when the ends of the DNA slowly get torn to bits over time. There are chains that attach to the ends of the DNA, they’re like shoe lace caps that keep the shoe laces from getting frayed. However over time these caps are also torn to bits and the DNA starts to fall apart, and the cell, and later the organism, dies.  Claire and Adam’s DNA likely have caps that cannot be torn apart over time, no tearing apart means no aging. Ironically there are cells in humans that can do this, cancer cells. Every cell in Claire’s body functions like a cancer. But somehow she isn’t dead. Probably because of her regenerative abilities.

That’s a least three separate mutations. And maybe more, if you count the fact that she would also have to have a crazy immune system to balance all this. This explains why there are so few characters in the Heroes universe that can regenerate. Only two, Claire and Adam. The number of mutations that have to line up perfectly is insane. If an individual had the ability to regenerate, but did not have an immune system that was strong enough to deal with all of it, they would die. If an individual couldn’t feel pain but does not regenerate they could die from accidental self-inflicted wounds in childhood.  Making Claire Bennet the specialist special of all.

I got my information on regeneration from the 2008 Nature paper “Wound repair and regeneration” which you can read the abstract of here.

The information on congenital insensitivity to pain came from the 2006 Nature paper “An SCN94 channelopathy causes congenital inability to experience pain”. You can read it here and I highly recommend it, in includes a lot of stuff I didn’t get a chance to talk about. Like incest. Ask me about the incest please.
Or you can read a National Geographic article about the same topic here.



#claire’s ability apparently first started working through her immune system (she’d never been sick in her life)   #oh and since it mentions the types of cells and stuff  #how does this tie in with claire and adam’s blood having healing qualities  #and what would a bone marrow transplant from a regenerator to a normal human do?  #heroes  via tersyne

I was actually going to originally talk about most of this, but I was afraid that it would get too confusing so I’m going to take a shot at it under the cut. Also note that I just learned about this about a month ago so I only have an extremely basic understanding of the immune system.

So as noted above, through her ability Claire has never been sick.The way that her body prevents illness, especially considering that she should have all sorts of infections from the under of open wounds that she sustains, is through producing lots of antibodies.

Antibodies are like little flags made by a certain type of white blood cell (B Cells) that attach to an invading microbe and tell your immune system to destroy it. Every antibody produced as a corresponding antigen on the invading microbe. And antigen is a marker on the outside of the microbe that lets your body know that the cell it’s looking at isn’t “self”, so like a protein that your body does not make or a special receptor only microbes have. There is one antibody for every antigen, meaning that there is no universal antibody that can be injected into someone to cure all diseases.

It seems reasonable to conclude then that Claire has all the antibodies. Literally, all of them. In truth this is a really large part of her ability. Her body not only heals rapidly but then efficiently kills all invading microbes.

Her and Adam’s blood can function as a cure-all for all diseases because of this. Let’s look at rabies as an example. Rabies is 100% deadly, there has never been a person in recorded history that can produce antibodies against rabies. So scientists made a synthetic antibody against rabies. If (at least in the United States) you go to the hospital and they find you have contracted rabies they will start an IV drip of these synthesized antibodies, covering the rabies microbe in synthetic antibodies so your body realizes it isn’t “self” and then can kill it. However because your body does not, and cannot, make these antibodies on it’s on you can’t develop your own antibodies against rabies in the future. If you went and got bit by a dog again your white blood cells still would not know how to make the rabies antibody. This explains why characters that have received Adam or Claire’s blood are not suddenly immune to all diseases.

How does Claire and Adam’s blood cure other things, like that time that Nathan got radiation poisoning and half his body got horribly burned? This is likely the proteins that Claire and Adam produce to delay clotting and scar formation are in the blood, so like the antibodies they are transferred along with the blood.

So in short blood is taken from Adam/Claire and inserted into Nathan. This blood contains every antibody as well as a protein that prevents scar formation so that regeneration has time to occur. However the ability isn’t permanently transferred because it’s only the proteins and antibodies that are transferred, and not the original genes. So over time Nathan would loose the ability to regenerate and to fight most diseases.

Now if there was a bone marrow transplant from someone who could regenerate to someone who could not the results would be complicated. So first off to transfer bone marrow many genetic markers must match. First we have to assume that there isn’t a mutation in one of these markers that prevents regenerators from donating to anyone (or they could have a mutation that allows them to donate to everyone, who knows). So the bone marrow is removed and put into a normal person. Several things could happen at this point:

There are two types of white blood cells that are produced in the bone marrow. There are the T Cells and the B Cells. The B Cells are the ones that make antibodies and are made and then mature (learn not to attack the “self”) in the bone marrow. The T Cells are made in the bone marrow and mature in the thymus (which is under your collar bone). T Cells work like air traffic control. They tell the B Cells what to do and they also can systemically destroy “self” cells that have been infected with a virus or have cancer.

Because B Cells mature in the bone marrow there is some evidence that some of the immunity from the donor may be transferred to the recipient (you can read the paper on that here although I barely understood it). So anyone that got a transplant from a regenerator could possibly produce all the antibodies.

However they wouldn’t be able to do anything with them, or the response would be very limited. This is because T Cells mature in the thymus. When the bone marrow is transplanted none of the mature T Cells are transferred along with it, leaving only stem cells that will become T Cells and the B Cells. So the recipient goes and makes their own T Cells, instead of the T Cells of the regenerator. So when a B Cell making the correct antibody bumps into the microbe expressing the corresponding antigen it goes back to the T Cells to tell them to start an immune response. However this is no corresponding T Cell, it was not transferred over and the normal person would likely not even be able to make a T Cell that corresponds because they are not a regenerator. So an immune response never even starts, the T Cell never can tell the B Cells to start making more antibodies to fight the infection, and the person will likely die. This is actually somewhat similar to how HIV works.

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