Genetics of aggression: Difference between revisions - Wikipedia
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Line 1: {{Short description|Determining if the trait is related to genetic factors}}
The field of [[psychology]] has been greatly influenced by the study of [[genetics]].<ref>{{Cite journal |last=Bouchard |first=Thomas J. |date=2004 |title=Genetic Influence on Human Psychological Traits: A Survey |url=http://journals.sagepub.com/doi/10.1111/j.0963-7214.2004.00295.x |journal=Current Directions in Psychological Science |language=en |volume=13 |issue=4 |pages=148–151 |doi= 10.1111/j.0963-7214.2004.00295.x|s2cid=17398272 |issn=0963-7214}}</ref> Decades of research
==History== Past The XYY genotype first gained wide notoriety in 1968 when it was raised as a part of a defense in two murder trials in [[Australia]] and [[France]]. In the [[United States]], five attempts to use the XYY genotype as a defense were unsuccessful—in only one case in 1969 was it allowed to go to a jury—which rejected it.<ref>{{cite book |author=Denno, Deborah H. |year=1996 |chapter=Legal implications of genetics and crime research |editor=Bock, Gregory R. |editor2=Goode, Jamie A. |title=Genetics of Criminal and Antisocial Behavior |pages=248–264 |location=Chichester |publisher=John Wiley & Sons |isbn= 0-471-95719-4}}</ref> Line 12: ==Heritability==
As with other topics in [[behavioral genetics]], aggression is studied in three main experimental ways to help identify what role [[genetics]] plays in the [[behavior]]: * [[Heritability]] studies – studies focused to determine whether a [[Phenotypic trait|trait]], such as aggression, is heritable and how it is inherited from parent to offspring. These studies make use of genetic linkage maps to identify [[genes]] associated with certain behaviors such as aggression. Line 20 ⟶ 17: * Genetic behavior [[correlation]] studies – studies that use scientific data and attempt to correlate it with actual human behavior. Examples include [[twin studies]] and [[adoption study|adoption studies]]. These three main experimental types are used in [[animal studies]], studies testing heritability and [[molecular genetics]], and gene/environment interaction studies. Recently, important links between aggression and genetics have been studied and the results are allowing scientists to better understand the connections.<ref name="Nelson06">{{cite book | ===Selective breeding=== The [[heritability]] of aggression has been observed in many animal strains after noting that some strains of birds, dogs, fish, and mice seem to be more [[aggressive]] than other strains. [[Selective breeding]] has demonstrated that it is possible to select for genes that lead to more aggressive behavior in animals.<ref name="Nelson06"/> Selective breeding examples also allow researchers to understand the importance of [[developmental]] timing for genetic influences on aggressive behavior. A study done in 1983 (Cairns) produced both highly aggressive male and female strains of mice dependent on certain developmental periods to have this more aggressive behavior expressed. These mice were not observed to be more aggressive during the early and later stages of their lives, but during certain periods of time (in their middle-age period) were more violent and aggressive in their attacks on other mice.<ref>{{cite book |author=Brain ===Mouse studies=== [[Mice]] are often used as a model for human [[genetics|genetic]] behavior since mice and humans have [[Homology (biology)|homologous]] [[genes]] coding for homologous [[proteins]] that are used for similar functions at some biological levels.<ref>{{cite book |author=Southwick, Charles H. |year=1970 |title=Animal Aggression: Selected Readings |location=London |publisher=Litton Educational Publishing Inc.}}</ref> Mice aggression studies have led to some interesting insight in human aggression. Using [[reverse genetics]], the [[DNA]] of genes for the receptors of many [[neurotransmitter]]s have been [[cloned]] and [[sequenced]], and the role of neurotransmitters in rodent aggression has been investigated using [[pharmacological]] manipulations. [[Serotonin]] has been identified in the offensive attack by male mice against intruder male mice. Mutants were made by manipulating a receptor for serotonin by deleting a gene for the serotonin receptor. These mutant male mice with the knockout [[alleles]] exhibited normal behavior in everyday activities such as eating and exploration, but when prompted, attacked intruders with twice the intensity of normal male mice. In offense aggression in mice, males with the same or similar [[genotype]]s were more likely to fight than males that encountered males of other genotypes. Another interesting finding in mice dealt with mice reared alone. These mice showed a strong tendency to attack other male mice upon their first exposure to the other animals. The mice reared alone were not taught to be more aggressive; they simply exhibited the behavior. This implicates the natural tendency related to biological aggression in mice since the mice reared alone lacked a parent to model aggressive behavior.<ref name="Bock96">{{cite book |author=Bock [[Oxidative stress]] arises as a result of excess production of reactive oxygen species in relation to defense mechanisms, including the action of [[antioxidant]]s such as superoxide dismutase 1 ([[SOD1]]). Knockout of the Sod1 gene was experimentally introduced in male mice leading to impaired [[antioxidant]] defense.<ref name="pmid25524980">{{cite journal |vauthors=Garratt M, Brooks RC |title=A genetic reduction in antioxidant function causes elevated aggression in mice |journal=J. Exp. Biol. |volume=218 |issue=Pt 2 |pages=223–7 |date=January 2015 |pmid=25524980 |doi=10.1242/jeb.112011 |doi-access=free }}</ref> These mice were designated (''Sod1-/-''). The ''Sod1-/-'' male mice proved to be more aggressive than both [[zygosity|heterozygous]] knockout males (''Sod1+/-'') that were 50% deficient in SOD1, and wild-type males (''Sod1+/+'').<ref name="pmid25524980" /> The basis for the association of oxidative stress with increased aggression has not yet been determined. ==Biological mechanisms== Experiments designed to study biological mechanisms are utilized when exploring how [[aggression]] is influenced by [[genetics]]. [[Molecular genetics]] studies allow many different types of behavioral traits to be examined by manipulating [[genes]] and studying the effect(s) of the manipulation.<ref>{{Cite journal |last=Stangor |first=Charles |last2=Walinga |first2=Jennifer |date=2019-06-28 |title=4.4 Is Personality More Nature or More Nurture? Behavioural and Molecular Genetics |url=https://openpress.usask.ca/introductiontopsychology/chapter/is-personality-more-nature-or-more-nurture-behavioral-and-molecular-genetics/ |journal=Introduction to Psychology |language=en}}</ref> ===Molecular genetics=== A number of [[molecular genetics]] studies have focused on manipulating candidate aggression [[genes]] in mice and other animals to induce effects that can be possibly applied to humans. Most studies have focused on [[polymorphism (biology)|polymorphisms]] of [[serotonin]] receptors, [[dopamine]] receptors, and [[neurotransmitter]] metabolizing [[enzyme]]s.<ref name="Tremblay05"/> Results of these studies have led to [[linkage analysis]] to map the serotonin-related genes and impulsive aggression, as well as dopamin-related genes and proactive aggression. In particular, the serotonin [[5-HT]] seems to be an influence in inter-male [[aggression]] either directly or through other molecules that use the 5-HT pathway. 5-HT normally dampens aggression in animals and humans. Mice missing specific genes for 5-HT were observed to be more aggressive than normal mice and were more rapid and violent in their attacks.<ref name="Nelson01">{{cite journal |author1=Nelson, Randy J. |author2=Chiavegatto, Silvana |year=2001 |title=Molecular basis of aggression |journal=Trends in Neurosciences |volume=24 |issue=12 |pages=713–9 |pmid=11718876 |doi=10.1016/S0166-2236(00)01996-2|s2cid=14070721 }}</ref> Other studies have been focused on neurotransmitters. Studies of a [[mutation]] in the neurotransmitter metabolizing enzyme [[monoamine oxidase A]] (MAO-A) have been shown to cause a syndrome that includes violence and impulsivity in humans.<ref name="Tremblay05"/> Studies of the molecular genetics pathways are leading to the production of [[pharmaceuticals]] to fix the pathway problems and hopefully show an observed change in aggressive behavior.<ref name="Nelson01"/> ==Human behavior genetics== In determining if a [[Phenotypic trait|trait]] is related to genetic factors or environmental factors, [[twin studies]] and adoption studies are used. These studies examine [[correlations]] based on similarity of a trait and a person's genetic or environmental factors that could influence the trait. [[Aggression]] has been examined via both twin studies and adoption studies. The human genetics related to aggression have been studied and the main genes have been identified. The [[Dat1|DAT1]] and [[DRD2]] genes are heavily related to the genetics of aggression.<ref>{{Cite journal |title= Aggression and polymorphisms in AR, DAT1, DRD2, and COMT genes in Datoga pastoralists of Tanzania|date=2013 |pmc=3818681 |last1=Butovskaya |first1=M. L. |last2=Vasilyev |first2=V. A. |last3=Lazebny |first3=O. E. |last4=Suchodolskaya |first4=E. M. |last5=Shibalev |first5=D. V. |last6=Kulikov |first6=A. M. |last7=Karelin |first7=D. V. |last8=Burkova |first8=V. N. |last9=Mabulla |first9=A. |last10=Ryskov |first10=A. P. |journal=Scientific Reports |volume=3 |page=3148 |doi=10.1038/srep03148 |pmid=24193094 |bibcode=2013NatSR...3E3148B }}</ref><ref>{{Cite journal |last1=Chen |first1=Thomas J. H. |last2=Blum |first2=Kenneth |last3=Mathews |first3=Daniel |last4=Fisher |first4=Larry |last5=Schnautz |first5=Nancy |last6=Braverman |first6=Eric R. |last7=Schoolfield |first7=John |last8=Downs |first8=Bernard W. |last9=Comings |first9=David E. |date=2005 |title=Are dopaminergic genes involved in a predisposition to pathological aggression? Hypothesizing the importance of "super normal controls" in psychiatricgenetic research of complex behavioral disorders |url=https://pubmed.ncbi.nlm.nih.gov/15964153/ |journal=Medical Hypotheses |volume=65 |issue=4 |pages=703–707 |doi=10.1016/j.mehy.2005.04.037 |issn=0306-9877 |pmid=15964153}}</ref> The DAT1 gene plays a role for its heavy relation to regulation of neurotransmission. The DRD2 Gene results in humans finding seemingly rewarding paths such as drug abuse. Through studies, DRD2 seems to be a risk factor in delinquency when children have related family trauma events.<ref>{{Cite journal |url=https://www.researchgate.net/publication/268786796 |last1=Boardman|last2= Menard |last3= Roettger|last4= Knight|last5= Boutwell |last6= Smolen |date=2014|title= Genes in the Dopaminergic System and Delinquent Behaviors Across the Life Course: The Role of Social Controls and Risks|journal= Criminal Justice and Behavior|volume= 41|issue=6|pages= 713–731 |doi= 10.1177/0093854813514227 |publisher= Sage |first1= Jason D. |first2= Scott | first3= Michael E. |first4= Kelly E. |first5= Brian B. |first6= Andrew | pmid= 25419014 | pmc= 4238108 }}</ref>
===Twin studies=== '''Twin studies''' === Genetics of aggression over time === Over time, studies pertaining to the genetics of aggression have improved, and become an interesting research topic for those looking for research opportunities. Experiments started in 1963 with the [[Milgram's experiment]]. The results of this experiment proved that in certain situations, people can be coaxed into aggression and violence. The next big experiment pertaining to the genetics of aggression took place in 1973 as part of the [[Stanford prison experiment]]. The conclusion drawn from this experiment was that in many cases, aggression is very unexpected at certain points. It was considered to be "elicited." This also revealed that aggression is often triggered in situations where someone feels an ideology that they hold a very powerful authority over someone else. It was concluded from both experiments that social aspects prove to be a big factor in the way people act aggressively. It was also concluded that every person has a potential to output aggressive behavior, but what is different between people is the extent of the point it takes to reach that output.{{citation needed|date=January 2024}} ==See also== Line 49 ⟶ 51: ==References== * Grigorenko, E.L. & Sternberg, R.J. (2003). The nature nurture issue. In A. Slater & G. Bremner (Eds.), ''An introduction to developmental psychology''. Malden, MA: Blackwell. * Pomp, D. (2010). [https://bmcgenomdata.biomedcentral.com/articles/10.1186/1471-2156-11-113 Genomic mapping of social behavior traits in a F2 cross derived from mice selectively bred for high aggression]. BCM Genetics, 11:113. doi:10.1186/1471-2156-11-113
{{Genetics}} {{DEFAULTSORT:Genetics Of Aggression}} [[Category:Aggression]] | |||