Genetics of Heroes

[jds1982]

I've been thinking about it for awhile, and I've come to the conclusion that the Heroes gene is recessive, as well as a mutation. Now I'm working with admittadly incomplete information. What I remember from high school biology states that there are two types of genes dominant and recessive. If you have any combination with the dominant gene you will have the dominant trait, and only with a combination of two recessive genes will you have a recessive trait.

We can use an H to represent the dominant heroes gene (which doesn't allow for powers) and an h to represent the recessive heroes gene (which does allow for powers) for ease of reference in our discussion of genetics.

Let's take two parents with dominate genes HH and HH, all of their children will have the HH combination of genes and be completely normal (or at least won't have superpowers). If we have one parent with one heroes recessive gene as in HH and Hh, they will have children with either HH combinations or Hh, 50% probability for both. Again none of these children will have powers.

If both parents have the Hh combination their children will have a 25% probability of having an HH child, a 50% chance of having an Hh child, and a 25% chance of having an hh child, so only 1 out of 4 chances of having a kid with powers. This may be the combination we see in Mohinder's family where one child had powers and the other does not.

What happens when a person with powers (hh) has a child with someone with only dominant genes (HH), all their kids will have the Hh combination and therefore no powers. If however someone with a power (hh) has kids with someone with an Hh gene pair they have a 50% chance of having no power kids (Hh) and a 50% chance of having kids with powers (hh). This is the possible combination at work in the Petrelli family (if indeed the mother has powers, although I guess it could have been the father).

The most obviously successful combination is that of two people with powers (hh). All of their children will have the gene pair that allows powers. We see this in Micah and Claire where both parents have powers.

Now obviously this is a little simplistic. It may be that powers are a combination of genes (in fact given the diversity of powers it is far more likely), but I thought it may spark discussion, and possible comment from people who are better versed in genetics than I am.

[Betelgeuze]

If i remember correctly Mohinder said that is a set of 4 genes that cause the powers. I don't think much can be said yet about the genes being dominant or recessive, since we haven't seen enough of Heroes with children. DL and Nikki both have powers, as do Claire's parents. We don't know if the Patrelli brothers parents have powers.

Also, the genes can be dominant, and the parents can have the genes, yet not manifest any powers. From what i understand is that the genes aren't necessary actieve in everyone. It appears that certain changes in environment are needed to activate the genes. If the parents didn't encounter any events that could lead to activation, they do not manifest any powers.

This would explain why people start to manifest powers at a later age. It also means that the children of parents who have manifested powers when they conceive the child, manifest at an earlier age. If the gene is on in the parents it will most likely be on in the child.

What happens when a person with powers (hh) has a child with someone with only dominant genes (HH), all their kids will have the Hh combination and therefore no powers. If however someone with a power (hh) has kids with someone with an Hh gene pair they have a 50% chance of having no power kids (Hh) and a 50% chance of having kids with powers (hh). This is the possible combination at work in the Petrelli family (if indeed the mother has powers, although I guess it could have been the father).

I hope you don't mind me correcting the parts i highlighted. If a parent with HH has a child a parent with hh, as you say all children will have Hh. Now assuming that there is complete dominance , which i think you meant, than the heterozygote (Hh) phenotype will be indistinguishable from the homozygote(HH). So all the children will have powers.

Hh= powers when there is complete dominance
hh= no powers

[jds1982]

I hope you don't mind me correcting the parts i highlighted. If a parent with HH has a child a parent with hh, as you say all children will have Hh. Now assuming that there is complete dominance , which i think you meant, than the heterozygote (Hh) phenotype will be indistinguishable from the homozygote(HH). So all the children will have powers.

Hh= powers when there is complete dominance
hh= no powers

I believe you are completely correct in your analysis about the homozygote and heterozygote, however if powers are recessive then hh would equal powers, while Hh would be no powers. That however is really just semantics, I just remember from biology that the capital letter represented the dominant gene while the lowercase letter represented the recessive gene.

[Betelgeuze]

I believe you are completely correct in your analysis about the homozygote and heterozygote, however if powers are recessive then hh would equal powers, while Hh would be no powers. That however is really just semantics, I just remember from biology that the capital letter represented the dominant gene while the lowercase letter represented the recessive gene.

You're right, that will teach me from replying to posts when i'm in a hurry, i read trait is dominant instead of recessive.

Anyway, what are you're thoughts on the epigenetics involved, that people can have the genes, yet not have them turned on?

[jds1982]

I think the show has shown that the genes aren't always "turned on", Parkman couldn't always detect thoughts, that's a recent development. Something in his environment must have turned the gene (or genes) on. I know that environment can have an effect on how genes are expressed. I have a theory that the heroes gene reacts to environmental stressors, but weirdly enough also reacts to willpower and thoughts. Look at Claire and Hiro, two vastly different powers and probably two vastly different methods for getting their powers. Claire's power is physical and automatic, and probably was sparked by her childhood disease. Hiro's power is more cerebral and was sparked by him thinking about it (or constipation). I mean how weird is that, the guy thinks about breaking the time/space continuum, and then he does? That's generally not how it works in comic books, you don't concentrate real hard and then have superpowers. If we look at more of them we see sort of the same thing, their powers are uniquely suited to them.
Parkman is a cop, suspiciousness and trying to get in peoples heads goes hand in hand with that job, what better way to do that then to read their thoughts? Nikki had an abusive father, so being able to fight back would be a benefit. D.L. is a criminal, walking through walls is incredibly handy when you're stealing things. Micah is a child of the digital age, he loves technology so why not have a power that meshes with that love. Sylar fixed watches, he had to be able to see flaws in things and correct them. Peter is very sensitive and able to pick up on how people feel, now he can pick up on their powers. Some of them like Ted and Nathan I can't really explain right now, but I haven't seen enough of their backstory to really make a call on them. Maybe Ted was a microwave repairman, and Nathan likes airplanes and skydiving, who knows?

[Betelgeuze]

If we look at more of them we see sort of the same thing, their powers are uniquely suited to them.

yes,the powers come from the same genes, yet each Hero manifests different powers. Like you said it makes sense that the powes are different, because our experiences shape our brain. And because everyone's brain is unique the effect of the products of the gene on the brain, and how the brain deals with it are different. Like drugs have the same general effects on people, but some effects occur in some people, but not others.

[jds1982]

Here's the thing though how could Hiro, in effect, choose his powers? Genes can't respond to conscious thought. You can't think real hard and change the color of your eyes (shapeshifters excluded). Maybe the genes code for a new brain structure. It would make sense, the brain has been the primary locus of human evolution.

[rosstaylor]

i think your attributing the heroes genetics to a very simple understanding of genetics, how do we know if they have an extra chromosome like downs (trisomy) or it's controlled by epistasis or something that we don't know about or understand

[jds1982]

i think your attributing the heroes genetics to a very simple understanding of genetics, how do we know if they have an extra chromosome like downs (trisomy) or it's controlled by epistasis or something that we don't know about or understand

I believe I said my reasoning was simplistic, it may very well be that they have an extra chromosone or something else weird. Is trisomy heritable, (downs is trisomy 21, right)? I assume it probably is.

[Betelgeuze]

i think your attributing the heroes genetics to a very simple understanding of genetics, how do we know if they have an extra chromosome like downs (trisomy) or it's controlled by epistasis or something that we don't know about or understand

Yes we are simplifying the genetics, i'm not a geneticist, don't now about the other posters. But since were dealing with a tv series were people have powers that are impossible for a human to have, and the writers themselves problably aren't geneticists either, i think the simplistic discussion can be forgiven don't you?

I think it's save to say that the trait isn't caused by trisomy, because the dr's Suresh would have noticed that right away.

And you're right epistasis(simplified, a gene or genes at one locus/loci alters the phenotypic expression of another gene) is a factor that has to be taken into account.

Here's the thing though how could Hiro, in effect, choose his powers? Genes can't respond to conscious thought. You can't think real hard and change the color of your eyes (shapeshifters excluded). Maybe the genes code for a new brain structure. It would make sense, the brain has been the primary locus of human evolution.

I think it is save to say that the gene products effect brain physiology/chemistry. Also Hiro might not have chosen his gift as much as sensed the way his power would manifest.

[jds1982]

I think it is save to say that the gene products effect brain physiology/chemistry. Also Hiro might not have chosen his gift as much as sensed the way his power would manifest.

Possibly, but it doesn't seem like anyone else "sensed" their powers, before they actually manifested. Peter is argueable in this case, but he dreamed about flying, which some people think was him siphoning Simone's dad's power.

[Kapitalist]

Here's a theoretical description of "Hero" genetics:

Hero abilities are the product of a four gene complex. More specifically two genes, each of which has two forms, or alleles. To be a "Hero", a person must have at least one of each of the dominant alleles. A non-Hero may either have two recessive "a" alleles, or two recessive "b" alleles.

* A - Hero gene 1 (dominant)
* a - non-Hero (recessive)
* B - Hero gene 2 (dominant)
* b - non-Hero (recessive)

These combinations will make a Hero:

* AABB
* AaBB
* AABb
* AaBb

These combinations will make a non-Hero:

* AAbb
* Aabb
* aaBB
* aaBb
* aabb

Two Hero parents can even have non-Hero children. These non-Heroes are produced by two Hero parents who have at least one recessive allele of the same gene:

AaBB x AaBB could produce

* AABB (1/4 chance) = Hero
* AaBB (1/2 chance) = Hero
* aaBB ( 1/4 chance) = non-Hero

AABb x AABb could produce

* AABB (1/4) = Hero
* AABb (1/2) = Hero
* AAbb (1/4) = non-Hero

However, the cross AABb x AaBB would produce all Hero offspring, since only one recessive allele of each gene could be inherited by any offspring:

* AABB (1/4) = Hero
* AABb (1/4) = Hero
* AaBB (1/4) = Hero
* AaBb (1/4) = Hero

The cross likely to produce the most non-Heroes from two Hero parents is, obviously, AaBb x AaBb, in which the offspring have a seven in sixteen chance of being a non-Hero.

Heroes born from two non-Heroes are produced if one parent has two "a" alleles and at least one "B" allele, while the other parent has two "b" alleles and at least one "A" allele. Because of this, they could produce Hero offspring:

AAbb x aaBB, for example, would produce all Hero offspring of the type AaBb.

Aabb x aaBb would produce Hero offspring in the proportion of one in four:

* AaBb = Hero
* Aabb = non-Hero
* aaBb = non-Hero
* aabb = non-Hero

Aabb x aaBB or AAbb x aabB would have a one in two chance of having Hero offspring.

[Kapitalist]

I have a theory that the heroes gene reacts to environmental stressors, but weirdly enough also reacts to willpower and thoughts.

Here's a theory along those lines:

Scattered throughout the supposedly unused "junk" portion of human DNA are HERVs (Human Endogenous Retroviruses). Endogenous retroviruses are RNA-based viruses that integrate their genetic material into the host's DNA, becoming part of the host's genome. Endogenous retroviruses exist in various forms in nearly all living things. Human Endogenous Retroviruses are the genetic fossils of ancient diseases, viruses that have entered into human DNA and persisted there in a dormant state for hundreds of thousands, if not millions, of years. Thousands of human endogenous retroviruses lie semi-dormant in the human genome. Some of these retroviruses operate as species-level retroviral infections, over tens of thousands or millions of years. The vector of evolutionary change is an infectious human endogenous retrovirus.

Through communication by pheromones, viruses, and sexuality, and through incorporation, selection, and editing of complexes of genes by a linguistically based and computational DNA, the genomes of individuals become part of an extensive, species-scale neural network that solves the problems of evolutionary adaptation.

Within the human genome are many "mobile" genes that can copy themselves and transport other genes from one position to another. These are called transposons, or retrotransposons, and they may play a huge role in organizing and regulating our genome. Retroviruses bear a distinct resemblance to retrotransposons.

The specific HERV that causes human evolution contains information gathered from previous mutations of species on what is a beneficial mutation, and can express itself, if under stress. A new species or subspecies the result of a programmed reshuffling of genes induced by a transfer of coded genetic signals. Their characteristics are largely determined by a kind of "meta-evolutionary" response.

A genome is capable of reacting to the outside environment through our immune system and stress hormones and chemicals. Endogenous retroviruses and mobile genes are frequently activated by stress hormones. The immune system acts as a kind of radar, informing the genome about environmental changes-and the stress of changing external and even social conditions determines the changes.

Proposed changes in morphology are communicated through sexual activity and retroviruses and stored up in populations in a genetic "set-aside" area within each individual. A library of records of past adaptations is used to "judge" new phenotypic proposals within the genome, individually and across the species. When environmental challenges arise, morphological changes are enacted in "suites" of mutually advantageous mutations. Possible variations are selected and edited extensively based on evidence culled from the environment by the immune system. The retrovirus creates a phenotype more suited to handle the perceived stress in the environment. In a sense, the genome is making an "educated guess" based on past evolutionary experience, giving the new variety of humans a better statistical chance to succeed by mixing and matching and even expanding upon varieties of past traits-smell, scent production, communication abilities in both the brain and elsewhere.

The decision within a species to produce a new type of organism, or subtly modify aspects of an old one, is made using genomic rules which are similar to the rules that also allow clusters of neurons, including brains, to solve problems that confront organisms in the environment.

There's is essentially a master biological computer in each species, a processor that tots up possible beneficial mutations. It makes decisions about what, where, and when something will change...makes guesses based on success rates from past evolutionary experience. Stress related hormones can affect expression of genes and this evolutionary library of possible new forms responds to stress produced hormones. If enough members of a the species are under stress, they exchange signals, reach a kind of quorum, and this triggers a genetic algorithm that compares sources of stress with a list of adaptations, evolutionary responses.

Simply put, when a certain threshold degree of stress in a species is detected by a genome, that genome dials through its library of possibilities for enhancement, punches in a selection, and releases one of these viral junk DNA segments to make the adjustment. The released DNA segments produce proteins in large volumes of slightly different molecular design to ensure success and avoid immunological destruction.

Thus, speciation can occur in bursts rather than over geological time because of an endogenous retrovirus that can be transmitted laterally between individuals, leading to "punctuated equilibrium." In many instances, gentler modifications occur, within geologically separated populations that, for a time at least, can still interbreed.

Within Heroes, something very different happens. The Hero genes cause the production of a HERV-activating hormone that activates the retroviruses in a way that prevents them from being transmitted outside the body. Along with that...without the external genomic signals of other humans on the effects of the endogenous retrovirus, rather than a homogenous mutation to spread across the species, they bring forth an "individual evolution" that is specifically tailored in response to the environmental and even psychological stressors on the person they reside in. Therefore every Hero develops a relatively unique mutation; their own special ability developed for them.