Wanderer gene — X-linked androgen receptor (AR) gene, short GGC repeat polymorphism
“a variant X-linked androgen receptor (AR) gene, predisposing the father to behaviors that include family abandonment, may be passed to their daughters causing early puberty, precocious sexuality, and behavior problems. The results of a study of 121 White males and 164 White females showed a significant association of the short alleles of the GGC repeat polymorphism of the AR gene with a range of measures of aggression and impulsivity, increased number of sexual partners, sexual compulsivity, and lifetime number of sex partners in males; and paternal divorce, father absence, and early age of menarche in females.” http://www.hopepress.com/html/abstract_91-100.html
X-linked means that this psychopathic candidate gene affects both males and females (female chromosomes of course are XX, males, XY), and androgen receptors ‘dock’ to male hormones such as testosterone, which is what we want, again for both females and males. Linda Mealey posited that psychopathy was sex-limited, i.e. required an androgen environment to ‘flower’.
[S]ociopaths are individuals on the extreme end of a normal distribution whose genetic component is (1) polygenic and (2) to a large degree, sexlimited. [Sex- limited genes, not to be confused with sex-linked genes, are those which are located on the autosomes of both sexes but which are triggered into expression only within the chemical/ hormonal microenvironment of one sex or the other. Common examples include beard and mustache growth in men, and breast and hip development in women.] If a large number of the many genes underlying sociopathy are triggered by testosterone or some other androgen, many more men than women will pass the threshold of the required number of active genes necessary for its outward expression. According to the two-threshold model, those females who do express the trait must have a greater overall “dose” or “genetic load” . . . https://pathwhisperer.info/2011/08/07/the-sociobiology-of-sociopathy-an-integrated-evolutionary-model-linda-mealey/
Ruthlessness gene — arginine vasopressin receptor 1A ” AVPR1a”, allele 334 or short RS3 repeats
Ebstein and his colleagues decided to look at AVPR1a because it is known to produce receptors in the brain that detect vasopressin, a hormone involved in altruism and ‘prosocial’ behaviour. Studies of prairie voles have previously shown that this hormone is important for binding together these rodents’ tight-knit social groups.
Ebstein’s team wondered whether differences in how this receptor is expressed in the human brain may make different people more or less likely to behave generously.
To find out, they tested DNA samples from more than 200 student volunteers, before asking the students to play the dictator game (volunteers were not told the name of the game, lest it influence their behaviour). Students were divided into two groups: ‘dictators’ and ‘receivers’ (called ‘A’ and ‘B’ to the participants). Each dictator was told that they would receive 50 shekels (worth about US$14), but were free to share as much or as little of this with a receiver, whom they would never have to meet. The receiver’s fortunes thus depended entirely on the dictator’s generosity.
About 18% of all dictators kept all of the money, Ebstein and his colleagues report in the journal Genes, Brain and Behavior1. About one-third split the money down the middle, and a generous 6% gave the whole lot away.
Long and short
There was no connection between the participants’ gender and their behaviour, the team reports. But there was a link to the length of the AVPR1a gene: people were more likely to behave selfishly the shorter their version of this gene.
It isn’t clear how the length of AVPR1a affects vasopressin receptors: it is thought that rather than controlling the number of receptors, it may control where in the brain the receptors are distributed. Ebstein suggests the vasopressin receptors in the brains of people with short AVPR1a may be distributed in such a way to make them less likely to feel rewarded by the act of giving.
Though the mechanism is unclear, Ebstein says, he is fairly sure that selfish, greedy dictatorship has a genetic component. It would be easier to confirm this if history’s infamous dictators conveniently had living identical twins, he says, so we could see if they were just as ruthless as each other. https://www.nature.com/news/2008/080404/full/news.2008.738.html
Genetic cocktail — psychopathy genetic markers
DRD2 A1, DRD4 7-repeat, 5HTTLPR/rs25531, COMPT (or COMT) Met108/158, MAOA-L (corrections welcome).
So, . . .which one, if any of these, is the no fellow-human-feeling, no empathy, no guilt gene, . . .where do full-genetic-dose psychopaths such as Stacey Castor or Michael Swango fall on this (actually they are not full spectrum full dose psychopaths — they did have the capacity to exercise restraint and to strategize, but on the other-humans-are-just-bugs continuum they are full dose)?