Author Topic: The Murder Gene  (Read 11626 times)

Offline Weltfrieden

Re:
« Reply #15 on: February 16, 2013, 10:34:11 PM »
Quote from: "antediluvian"
Thought I read somewhere about a study of infants born in families with generations of violence and adopted by mild mannered couples.   When these adoptive babies became children and adolescents they were more inclined toward rough and aggressive behavior than infants adopted from non-violent families.
That's likely not a sign of it being genetic but more so that the violence they experienced at a young age was enough to have an impact on them later in life.

Re: Re:
« Reply #16 on: February 16, 2013, 10:36:22 PM »
Quote from: "Rasputin"
Quote from: "antediluvian"
Thought I read somewhere about a study of infants born in families with generations of violence and adopted by mild mannered couples.   When these adoptive babies became children and adolescents they were more inclined toward rough and aggressive behavior than infants adopted from non-violent families.
That's likely not a sign of it being genetic but more so that the violence they experienced at a young age was enough to have an impact on them later in life.
They were adopted as infants, removed from the birth family, were not exposed to violence in the adoptive families.
I always wondered why having balls was equated with "strength".  Balls are sensitive and delicate, actually.   Better to grow a vagina.  Those things can take a pounding - and pop out a live human being the size of a watermelon.

Offline Weltfrieden

(No subject)
« Reply #17 on: February 16, 2013, 10:37:50 PM »
Hmm, I missed the word infants originally. That is curious, perhaps it is genetic after all.

*goes back to the drawing board*

Offline AllPurposeAtheist

Re: The Murder Gene
« Reply #18 on: February 16, 2013, 10:42:03 PM »
I'm pretty sure jmpty is a closet mass murderer by the looks of official military photo. Those glasses would make me want to kill for sure.
viewtopic.php?f=1&t=91&p=1627#pageheader
All hail my new signature!

Admit it. You're secretly green with envy.

Offline Weltfrieden

(No subject)
« Reply #19 on: February 16, 2013, 10:49:36 PM »
Found a good article about it, turns out y'all are onto something.

Quote from: "[url=http://serendip.brynmawr.edu/bb/neuro/neuro04/web2/apatel.html
http://serendip.brynmawr.edu[/url]"][center:4s6mnxzv]Genetic basis for Violence

amar patel
[/center:4s6mnxzv]
Aside from the strict science and reporting in genetic based cases, one of the major points that have been stressed in all studies of genes for behaviorism is the minimal affect they have compared to any environmental factors. All scientists agree on the idea that behavior stems from the nervous system, but the real question has been the degree that the nurturing environment plays in initiating certain behaviors. The easiest breakdown is comparing violence genes to those for alcoholism. Since it is assumed that alcoholism is genetic, one must understand that the genes cannot take any affect until someone is exposed to alcohol. In the same way, violence must be initiated by a case of abuse before the cycle can be perpetuated. It is quite obvious that no matter what chemicals or genes are found to be related to violence, all cases start from the impact of a patient's surroundings.

Although all violence was traditionally thought to be in the realm of sociology, or psychology, we are now finding increasing evidence of its biological initiation. Many recent studies support the notion of a genetic "deficiency" causing aggressive behavior. These genes code for certain enzymes that are responsible for the metabolism or synthesis of neurotransmitters. This genetic analysis will show the genes coding for the Monoamine oxidase (MAOA) and Tryptophan hydroxylase (TPH) enzymes (catalyzing proteins) have been linked to specific cases of violent behavior.

Each of these enzymes works on neurotransmitters to control activity in the brain. A neurotransmitter is essentially a type of chemical that carries a signal across a synapse between neurons. The primary neurotransmitters that have been associated with the onset of aggression or violence are Serotonin (5-HT), Norepinephrine, and Dopamine. These neurotransmitters are three of the most common chemicals found in the brain. Serotonin is responsible for different moods, appetite, sexual activity, homeostasis, and sleep. Norepinephrine is affected by stress and moods in the brain; it is also involved in the sympathetic nervous system. (2) Dopamine is used to regulate emotion, the "pleasure center" of the brain, and motivation. (3)

In order to comprehend the function and relation of neurotransmitters better, one must understand the way in which neurons communicate via synapses. A common nerve cell holds a partially negative charge, relative to its outside environment. There are various channels that allow the flow of positive sodium ions into the nerve cell. These sodium channels are activated when the channel prior to it has moved in ions. This essential "domino effect" of allowing positive ions into the cell creates what is known as an action potential. When the action potential reaches the end of the axon it will allow for the intake of calcium ions, and the release of synaptic vessels which contain the neurotransmitter chemicals. When these vessels reach the axon's cell membrane they release their neurotransmitters into the synaptic cleft. All of these neurotransmitters are taken up by the dendrites of the next cell's membrane.

The MAOA enzyme operates on the molecules leftover in the axon. Monoamine Oxidase is an enzyme used to metabolize the neurotransmitters Serotonin, Norepinephrine, and Dopamine. The purpose of the MAOA enzyme is essential to inhibit the reactivity of the neurotransmitters. (4) Any leftover neurotransmitters will be broken down by the MAOA enzymes. Since this enzyme is translated from a gene that is located on the X-chromosome, of which women have 2 copies and males only one, males have a greater probability of having a deficiency of the enzyme.

Another interesting aspect of the study conducted on MAOA stated that the link between violence and genetic mutations in which no genes for MAOA existed, proved inconclusive for an entire population. (4) The reason that these results are not conclusive on the entire population is in relation to the entire nature versus nurture battle. On a whole, the majority of the population has not experienced abusive situations. After narrowing the search criteria, the research did eventually find links between the MAOA enzyme and aggression. Such results further the notion that genetic backgrounds are not utilized without a behavioral initiator.

The most cohesive link was found between the MAOA enzyme activity and adolescent conduct disorder in 'maltreated' males. (4) The conclusions drawn from these studies show that although there are instances of the MAOA enzyme being completely deficient, these cases are rare. There is, however, a large portion of the population which has a low MAOA enzyme activity. (4) Whenever neurotransmitters are released, from fear etc., they will remain in the synaptic cleft and cause more aggressive behavior. In previously abused children, this activity bolsters violent behavior by stopping Serotonin activity. (4)

The other enzyme that has been equally promoted as a cause of violent is TPH, an enzyme which is concerned with limiting the rate of synthesis of the neurotransmitter Serotonin. (5) The biology behind the TPH enzymes makes scientists aware of the fact that it is the only catalyst in the reaction producing Serotonin and therefore can limit its production.(1) Many studies have shown that altered Serotonergic activity exists in many males with suicidal and aggression issues. (6) Any deficiency in the amount of TPH produced creates a dearth of Serotonin in areas of the brain which use it to hinder impulsive behavior. Many published experiments show that in order to understand the prevalence of cases with TPH deficiency better, one must look at the genetics basis of the enzyme's production.

The TPH allele is associated with the gene A218C. One of the studies conducted with TPH enzymes showed that people with a single nucleotide substitution on the TPH gene, creating an A779C single, had more issues with aggression.(5) The presence of the A779C is what leads to a deficiency in the amount of TPH present in the brain.(1) The lack of this TPH will consequently cause a lower than normal level of Serotonin production. The low Serotonin level will lead to difficulties in inhibiting impulsive behaviors.

As seen in the MAOA enzymes, the lack of the TPH enzyme is also not something that is found in a majority of the population. When examining the various scientific studies, one cannot help but understand that genetics is not the sole factor in violent behavior. The scarcity of cases of violent behavior with relation to deficient enzymes shows that not all violent behavior can be accounted for through genetics. This is not to say that there is no genetic basis for behavior in genes, but one can safely maintain the notion that outside influence plays a larger role in the behavior of a person.

(See original article for references)

Re:
« Reply #20 on: February 16, 2013, 10:54:17 PM »
Quote from: "Rasputin"
Found a good article about it, turns out y'all are onto something.

Quote from: "[url=http://serendip.brynmawr.edu/bb/neuro/neuro04/web2/apatel.html
http://serendip.brynmawr.edu[/url]"][center:su038zks]Genetic basis for Violence

amar patel
[/center:su038zks]
Aside from the strict science and reporting in genetic based cases, one of the major points that have been stressed in all studies of genes for behaviorism is the minimal affect they have compared to any environmental factors. All scientists agree on the idea that behavior stems from the nervous system, but the real question has been the degree that the nurturing environment plays in initiating certain behaviors. The easiest breakdown is comparing violence genes to those for alcoholism. Since it is assumed that alcoholism is genetic, one must understand that the genes cannot take any affect until someone is exposed to alcohol. In the same way, violence must be initiated by a case of abuse before the cycle can be perpetuated. It is quite obvious that no matter what chemicals or genes are found to be related to violence, all cases start from the impact of a patient's surroundings.

Although all violence was traditionally thought to be in the realm of sociology, or psychology, we are now finding increasing evidence of its biological initiation. Many recent studies support the notion of a genetic "deficiency" causing aggressive behavior. These genes code for certain enzymes that are responsible for the metabolism or synthesis of neurotransmitters. This genetic analysis will show the genes coding for the Monoamine oxidase (MAOA) and Tryptophan hydroxylase (TPH) enzymes (catalyzing proteins) have been linked to specific cases of violent behavior.

Each of these enzymes works on neurotransmitters to control activity in the brain. A neurotransmitter is essentially a type of chemical that carries a signal across a synapse between neurons. The primary neurotransmitters that have been associated with the onset of aggression or violence are Serotonin (5-HT), Norepinephrine, and Dopamine. These neurotransmitters are three of the most common chemicals found in the brain. Serotonin is responsible for different moods, appetite, sexual activity, homeostasis, and sleep. Norepinephrine is affected by stress and moods in the brain; it is also involved in the sympathetic nervous system. (2) Dopamine is used to regulate emotion, the "pleasure center" of the brain, and motivation. (3)

In order to comprehend the function and relation of neurotransmitters better, one must understand the way in which neurons communicate via synapses. A common nerve cell holds a partially negative charge, relative to its outside environment. There are various channels that allow the flow of positive sodium ions into the nerve cell. These sodium channels are activated when the channel prior to it has moved in ions. This essential "domino effect" of allowing positive ions into the cell creates what is known as an action potential. When the action potential reaches the end of the axon it will allow for the intake of calcium ions, and the release of synaptic vessels which contain the neurotransmitter chemicals. When these vessels reach the axon's cell membrane they release their neurotransmitters into the synaptic cleft. All of these neurotransmitters are taken up by the dendrites of the next cell's membrane.

The MAOA enzyme operates on the molecules leftover in the axon. Monoamine Oxidase is an enzyme used to metabolize the neurotransmitters Serotonin, Norepinephrine, and Dopamine. The purpose of the MAOA enzyme is essential to inhibit the reactivity of the neurotransmitters. (4) Any leftover neurotransmitters will be broken down by the MAOA enzymes. Since this enzyme is translated from a gene that is located on the X-chromosome, of which women have 2 copies and males only one, males have a greater probability of having a deficiency of the enzyme.

Another interesting aspect of the study conducted on MAOA stated that the link between violence and genetic mutations in which no genes for MAOA existed, proved inconclusive for an entire population. (4) The reason that these results are not conclusive on the entire population is in relation to the entire nature versus nurture battle. On a whole, the majority of the population has not experienced abusive situations. After narrowing the search criteria, the research did eventually find links between the MAOA enzyme and aggression. Such results further the notion that genetic backgrounds are not utilized without a behavioral initiator.

The most cohesive link was found between the MAOA enzyme activity and adolescent conduct disorder in 'maltreated' males. (4) The conclusions drawn from these studies show that although there are instances of the MAOA enzyme being completely deficient, these cases are rare. There is, however, a large portion of the population which has a low MAOA enzyme activity. (4) Whenever neurotransmitters are released, from fear etc., they will remain in the synaptic cleft and cause more aggressive behavior. In previously abused children, this activity bolsters violent behavior by stopping Serotonin activity. (4)

The other enzyme that has been equally promoted as a cause of violent is TPH, an enzyme which is concerned with limiting the rate of synthesis of the neurotransmitter Serotonin. (5) The biology behind the TPH enzymes makes scientists aware of the fact that it is the only catalyst in the reaction producing Serotonin and therefore can limit its production.(1) Many studies have shown that altered Serotonergic activity exists in many males with suicidal and aggression issues. (6) Any deficiency in the amount of TPH produced creates a dearth of Serotonin in areas of the brain which use it to hinder impulsive behavior. Many published experiments show that in order to understand the prevalence of cases with TPH deficiency better, one must look at the genetics basis of the enzyme's production.

The TPH allele is associated with the gene A218C. One of the studies conducted with TPH enzymes showed that people with a single nucleotide substitution on the TPH gene, creating an A779C single, had more issues with aggression.(5) The presence of the A779C is what leads to a deficiency in the amount of TPH present in the brain.(1) The lack of this TPH will consequently cause a lower than normal level of Serotonin production. The low Serotonin level will lead to difficulties in inhibiting impulsive behaviors.

As seen in the MAOA enzymes, the lack of the TPH enzyme is also not something that is found in a majority of the population. When examining the various scientific studies, one cannot help but understand that genetics is not the sole factor in violent behavior. The scarcity of cases of violent behavior with relation to deficient enzymes shows that not all violent behavior can be accounted for through genetics. This is not to say that there is no genetic basis for behavior in genes, but one can safely maintain the notion that outside influence plays a larger role in the behavior of a person.

(See original article for references)

You are such a sweety for lookin' that up for me.
I always wondered why having balls was equated with "strength".  Balls are sensitive and delicate, actually.   Better to grow a vagina.  Those things can take a pounding - and pop out a live human being the size of a watermelon.

Offline bennyboy

(No subject)
« Reply #21 on: February 16, 2013, 11:04:35 PM »
The last lines of that article seem off to me.  Examining specific alleles is fine, but not finding a strong relation between them and behavior doesn't really mean anything: it just means there is more going on than they've put their finger on.

I think twin and adoption studies are the rule for now (scroll up to see the text it's from):

http://http://books.google.ca/books?id=rxd2305M2gQC&pg=PA110
Insanity is the only sensible response to the universe.  The sane are just making stuff up.

Offline Weltfrieden

Re: Re:
« Reply #22 on: February 16, 2013, 11:15:59 PM »
Quote from: "antediluvian"
You are such a sweety for lookin' that up for me.
No problem. *tips hat* I was quite curious myself. :)

Re: The Murder Gene
« Reply #23 on: February 17, 2013, 12:48:30 AM »
Predisposition to alcoholism does have a genetic component, yes. Much research has been done on 5-HTT alleles which suggest a certain polymorphism is linked to alcoholism; principally this research has been done in rhesus macaques with the added variable of rearing. The interesting thing is that when rhesus infants who had a genetic predisposition to alcoholism were reared with a good mother, they drank less than even those who had a good mother and did not have the risk allele.

I bring this up because the genetic predisposition for alcoholism in this case is also directly involved in the reuptake of serotonin. The research also goes on to describe that there are only certain primate species which have the 5-HTT polymorphisms which happen to include rhesus macaques, ourselves, and a few others. This is interesting because these primates (non-human and otherwise) also tend to behave fairly aggressively in certain paradigms, which may suggest the gene is also linked to aggression. I would think aggression is linked to murder =P

Bottom line: it's never as simple as "genetic predisposition." Epigenetics and environmental factors play a big role.

http://www.youtube.com/watch?v=lFACM5gcJYY

http://www.nichd.nih.gov/about/staff/Pa ... 0010152932
Quote from: \"azmhyr\"
Quote from: \"quoting\"
New Testament doesn\'t Justify the banning of gays from anywhere.
Well, the old testament permabans them from life tho.

Offline bennyboy

Re: The Murder Gene
« Reply #24 on: February 17, 2013, 06:37:11 AM »
Good video.

I think at least anecdotally it shows that behavior is multi-sourced, even in one person.  Feelings of guilt or sympathy might prevent a bad behavior, but so could a world view in which the person is self-defined as "good," or a strong analytic mind that comprehends the idea of greater good.
Insanity is the only sensible response to the universe.  The sane are just making stuff up.

Re: The Murder Gene
« Reply #25 on: February 17, 2013, 11:10:51 AM »
Quote from: "drunkenshoe"
Yes genetics is the first reason.

Not so much the first reason as one of the factors. Case in point, Phineas Gage.
Quote from: \"azmhyr\"
Quote from: \"quoting\"
New Testament doesn\'t Justify the banning of gays from anywhere.
Well, the old testament permabans them from life tho.

Re: The Murder Gene
« Reply #26 on: February 17, 2013, 11:49:35 AM »
Interesting.
So far, just about everything they have searched for has a "predisposition" gene (or more accurately, set of alleles).  From diseases to behaviors, it's all already in your genes somewhere.  There are probably a lot of people out there walking around with the "murder gene", but they were not raised in an environment that triggered it.  Just like having the breast cancer gene doesn't mean you WILL get breast cancer, just that you are more likely to than a person without that that gene to get it, given the right (or wrong) circumstances.  That's why when you do screenings, they assess your risk based on not just the gene, but the gene plus many environmental factors.

Imagine, someday they will probably screen kids and adults for violent predisposition, as well as a host of diseases, by looking at their genetic code and environment together.
"A life is like a garden. Perfect moments can be had, but not preserved, except in memory.  LLAP"
Leonard Nimoy

Offline bennyboy

Re: The Murder Gene
« Reply #27 on: February 17, 2013, 12:28:15 PM »
Quote
Imagine, someday they will probably screen kids and adults for violent predisposition, as well as a host of diseases, by looking at their genetic code and environment together.
Or, they'll require all expectant mothers to do a prescreening in order to get a "birthing permit."
Insanity is the only sensible response to the universe.  The sane are just making stuff up.

(No subject)
« Reply #28 on: February 17, 2013, 12:39:11 PM »
Antisocial personality disorder is said to be genetically based but typically has environmental factors, such as family relations, that trigger its onset. Traumatic events can lead to a disruption of the standard development of the central nervous system, which can generate a release of hormones that can change normal patterns of development.[11] One of the neurotransmitters that have been discussed in individuals with ASPD is serotonin.
 
A recent meta-analysis of 20 studies showed a correlation between ASPD and serotonin metabolic 5-hydroxyindoleacetic acid (5-HIAA). The study found a reasonable effect size (5-HIAA levels in antisocial groups were 0.45 standard deviation lower than in non-antisocial groups)[12]
 
J.F.W. Deakin of University of Manchester's Neuroscience and Psychiatry Unit has discussed additional evidence of 5HT's connection with antisocial personality disorder. Deakin suggests that low cerebrospinal fluid concentrations of 5-HIAA, and hormone responses to 5HT, have displayed that the two main ascending 5HT pathways mediate adaptive responses to post and current conditions. He states that impairments in the posterior 5HT cells can lead to low mood functioning, as seen in patients with ASPD. It is important to note that the dysregulated serotonergic function may not be the sole feature that leads to ASPD but it is an aspect of a multifaceted relationship between biological and psychosocial factors.
 
While it has been shown that lower levels of serotonin may be associated with ASPD, there has also been evidence that decreased serotonin function is highly correlated with impulsiveness and aggression across a number of different experimental paradigms. Impulsivity is not only linked with irregularities in 5HT metabolism but may be the most essential psychopathological aspect linked with such dysfunction.[13] In a study looking at the relationship between the combined effects of central serotonin activity and acute testosterone levels on human aggression, researchers found that aggression was significantly higher in subjects with a combination of high testosterone and high cortisol responses, which correlated to decreased serotonin levels.[14] Correspondingly, The Diagnostic and Statistical Manual of Mental Disorders classifies "impulsiveness or failure to plan ahead" and "irritability and aggressiveness" as two of the seven criteria in diagnosing someone with ASPD.
 
Some studies have found a relationship between monoamine oxidase A and antisocial behavior, including conduct disorder and symptoms of adult ASPD, in maltreated children.
 
[edit] Limbic neural maldevelopment
 
Cavum septum pellucidum (CSP) is a marker for limbic neural maldevelopment.[15] One study found that those with CSP had significantly higher levels of antisocial personality, psychopathy, arrests and convictions compared with controls.[15]
 
[edit] Cultural influences
 
Robert D. Hare has suggested that the rise in antisocial personality disorder that has been reported in the United States may be linked to changes in cultural mores, the latter serving to validate the behavioural tendencies of many individuals with ASPD.[16] While the rise reported may be in part merely a byproduct of the widening use (and abuse) of diagnostic techniques,[citation needed] given Eric Berne's division between individuals with active and latent ASPD - the latter keeping themselves in check by attachment to an external source of control like the law, traditional standards, or religion[17] - it has been plausibly suggested that the erosion of collective standards may indeed serve to release the individual with latent ASPD from their previously prosocial behaviour.[18]
 
There is also a continuous debate as to the extent to which the legal system should be involved in the identification and admittance of patients with preliminary symptoms of ASPD.[19]
 
[edit] Environment
 
Some studies suggest that the social and home environment has contributed to the development of antisocial behaviour.[20] The parents of these children have been shown to display antisocial behavior, which could be adopted by their children.[20]
???  ??

Re:
« Reply #29 on: February 17, 2013, 12:51:25 PM »
Quote from: "Rasputin"
I don't think it is genetic, I think it has all to do with how a person is raised as a child. If a child is raised in a violent environment then they are more likely to become violent adults if they aren't removed from that environment soon enough.

Then how would you explain patients with Klinefelter syndrome that have a greater risk of being violent?
Winner of WitchSabrinas Best Advice Award 2012


We can easily forgive a child who is afraid of the dark; the real
tragedy of life is when men are afraid of the light. -Plato