Androgen Receptor Gene and Aggression in the Japanese Akita Inu

These individual differences are of the highest importance for us, for they are often inherited, as must be familiar to every one; and they thus afford materials for natural selection to act on and accumulate, in the same manner as man accumulates in any given direction individual differences in his domesticated productions. — Charles Darwin, On the Origin of Species

One of the regular readers/posters has mentioned her Akita a few times so I decided to learn a little more about the breed.  My preference has always leaned towards the Pastoral and Gundog groups (Herding & Sporting), so I was only familiar with the basics of the Akita. For example, I was unaware of the American/Japanese split among the breed fanciers.

秋田犬

Japanese Akita Inu. 秋田犬

In my exploration of the breed I came across as study on the behavioural genetics of the Akita. But before I get to the study, a quick blurb about genes and animal behaviour seems appropriate.

Some Background

Even before the advent of modern molecular methods, there was strong indication that certain personality traits were inherited; today the short list includes DRD4, 5-HTT, MAO, SLC6A4, DAT1, BDNF, COMT, vasopressin, TH, cortisol and the subject of this study, the androgen receptor gene. All these genes have been linked to various personality traits in human or non-human animals. Many of the ones mentioned above and many more not mentioned influence the same or related traits, so these genes are not only interacting with the environment but also with each other.

As I mentioned in Nature vs Nurture, genes don’t act in a vacuum. They don’t create personality, they are part of complex and dynamic set of interacting variables that play a role in the development of personality and behavior. Genes do not create behavior. No gene CAUSES aggression or novelty seeking or herding or social bonding or anxiety or any other trait. There is no ball gene, dominance gene or pee-in-the-house gene; rather they set the stage for environment to act; they tilt the odds (usually only slightly) towards one option over others.

The Study

The study Androgen receptor gene polymorphisms are associated with aggression in Japanese Akita Inu” (doi: 10.1098/rsbl.2011.0087) explores the relationship between gene variations (polymorphism = many forms) of the Q2 region of exon 1 in the androgen receptor (AR) gene and personality traits in the Japanese Akita Inu.

To minimize the variables, all dogs in the study were fawn coloured, intact and sexually mature who lived inside as pets and all had male owners. Other aspects of the study:

  • 3 alleles of AR gene were detected
  • the alleles differed in the number of CAG repeats in exon 1
  • (CAG)23, (CAG)24 and (CAG)26
  • allele frequency varies with coat

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For the analysis the researchers designated the S (short) for the 23 variant and the L (long) to the 24 and 26 versions.  This makes the five different genotypes: S/ and L/ for the males and S/S, S/L & L/L for the females.

You might be wondering why the males only have single letter designation. It’s because the gene for the androgen receptor is found in the X chromosome, this means females (XX) get two copies and males (XY) get only one. The astute reader is thinking, “Doesn’t that mean the females are doubling up on gene products?”  The answer is “No.” It is because of something known as chromosome dosage compensation – if you’ve ever seen a Calico cat then you’ve seen dosage compensation in action. The technicalities are not germane to this article but it is a fascinating topic so I’ve included a couple of links in the notes for the biology enthusiast.

The Findings

The authors report higher aggressive scores in males (no effect on females) carrying the short genotype [(CAG)23] allele than those with the long genotype [(CAG)24 or (CAG)26] variant. There was no observed difference in the other 4 personality traits surveyed – playfulness, distractability, neuroticism, sociability in either gender.

Finally, if you finish reading this article and you are thinking, “My/that Akita is aggressive because he has a short (CAG23) AR gene”, then I’ve done a terrible job.

Further Reading

Dosage compensation

http://www.nature.com/scitable/blog/student-voices/x_chromosome_inactivation_in_the

http://www.nature.com/nsmb/journal/v19/n1/full/nsmb.2218.html

http://www.pnas.org/content/109/14/5346.full

https://en.wikipedia.org/wiki/X-inactivation

Reference

Konno A, Inoue-Murayama M and Hasegawa T. Androgen receptor gene polymorphisms are associated with aggression in Japanese Akita Inu. Biol. Lett. 2011 7, 658-660.  doi: 10.1098/rsbl.2011.0087

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11 thoughts on “Androgen Receptor Gene and Aggression in the Japanese Akita Inu

  1. I was getting a little lost on the technical, but what was the difference with the color of the dog? My male was white, and was intact until 14 months. His aggressive behavior was directed at most other dogs. But that only became an issue after his first encounter with a Dalmatian when he was one. Prior to being attacked, he had no problems with other dogs. After, it was a continuous problem, no matter how much training and conditioning I tried. It seemed to be in his nature. His sire was an unpredictable dog also, which ended his show career. One minute my Akita was calm and obedient, then out of nowhere he would attack another dog while on his leash if one got too near. He seemed to remember that one confrontation and act on the offense thereafter. Any thoughts?

    • The frequency of the genes varies with the color. For example 70% of the Brindle population has the short (23) variant associated with greater aggression, but only 52% of Fawn and White dogs have it. As to your dog, of course it’s impossible to say why some dogs can recover while others remember the incident and it forever changes them. We can’t point to any specific gene, but the indications are that there is a strong genetic component. It might be one of those case that his genetics were primed for such an incident making him resistant (I don’t think any dog is immune) to behavior modification.

      • He knew the consequence of his action, yet still did it anyway. He would get a ‘long time out’ with no interaction with me. I acted like he was not there and completely ignored him. My husband would feed him, not me. And if you know Akita’s, this really is a punishment because they are so loyal to their owner. All I could think of was he felt as if he was protecting me because I was always between him and the other dog (to prevent him from ‘losing it’). Maybe it was this action that precipitated the confrontation.

  2. Hi,
    Very interesting, thanks for sharing! Could you clarify how did they define and measure the aggression? And what sort of aggression was it? And how did they account for differences in upbringing and environment of dogs? Thanks!

    • 100 fawn-coloured dogs (54 males and 46 females)
      All dogs were kept in their owner’s house as pets.
      All subjects were intact and sexually mature dogs
      Age ranging from 13 months to 7 years.
      All owned by middle age men

      And while it may sound strange, statistically the individual environment doesn’t make a difference.

      Personality was based on a 30 question survey based on a 6 point scale.

      Test restest reliability was done by asking 20 (10M dogs, 10F dogs) of the participants to redo the questionnaires 3-4 weeks later, with r=0.85 for aggressiveness. Table 2 indicates how aggressiveness was defined.

      Table 2. Items of the aggressiveness scale applied in the present study.
      adjective defining statement
      dominant behaves only as he/she pleases and becomes aggressive when interrupted
      defiant becomes aggressive, even towards you or other family members when he/she is annoyed
      moody seems to be in a bad mood constantly and displays mood swings frequently
      irritable impatient and gets angry at people as well as other dogs that he/she dislikes
      aggressive threatens or initiates fights with people as well as other dogs, that he/she dislikes

  3. Table 2 is telling. They did not include those that only get aggressive towards other animals, and not people. Is disliking and annoyance quantifiable? Like, how can you really tell the dog’s motivation for the behavior? Just asking.

  4. Pingback: Genes, Environment, Breeding (The 20 Principles) | Roger Abrantes

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