Behaviour needs explanations – the how and the why are as important as the consequences. If we analyse the genetic and epigenetic differences between domestic and wild animals, we can build a biological model for stress behaviour in animals and, possibly, humans.

Today I and my research group focus on the genetic and epigenetic backgrounds of stress induced behaviour, tackling domestication and animal welfare using a fundamental approach.

Epigenetics encode behaviour

Professor Per Jensen med nyckläckta kycklingarEpigenetics encompasses all the mechanisms involved in orchestrating a genome, the factors regulating when and how much a gene is expressed. We are especially interested in DNA methylation, which is the chemical modification of the cytosine base of DNA, which in turn affects the transcription of the affected gene.

The interesting thing about epigenetics is that, unlike genetics, it is dynamic. Thus epigenetic variation responds to environmental input. For example, an animal that experiences stress will have epigenetic modifications to its genome, which in turn will affect how it responds in other situations.

One key factor about epigenetics is that some changes can be transferred across generations. Thus the stress experienced by one individual may change the behaviour and biology of its descendants, perhaps even several generations away.

Domestication as a model for stress

My AVIAN Behavioural Genomics and Physiology research group at Linköping University uses domestication as a model system for the evolution of behaviour. This takes advantage of the fact that during domestication animals have adapted to living with humans, and become less susceptible to stress. Thus, by comparing domestic animals with their wild ancestors, it is possible to analyse the genetic mechanisms involved in stress behaviour.

At the AVIAN group we work mainly with chickens. One example of our research is the long term effects of stress depending on when in life it is experienced: a newly hatched chicken that experienced stress suffers quite different effects from it than a chicken that experiences the exact same amount of stress ten or fifteen weeks later. This discrepancy is currently a key area of research for us.

Another of our major research areas is, in spite of the group's name, dogs. Dogs are the oldest domesticated species, descending from wild wolves, and have evolved a set of unique behaviour strategies to cope with the stress of life: they use humans as emotional referents and companions. An unprecedented richness in breed diversity and behaviour makes the dog a valuable model for studying genetic and epigenetic mechanisms in behaviour. 

Unique facilities

Our research group is unique in the world in the broadness of the facilities we have available. We control our research from the point of breeding and hatching the animals, through infancy in the university's own chicken coops, to our behaviour laboratories equipped to handle advanced behaviour recording, to the physiology laboratories equipped for various types of surgery and measurements on animals. And all of this is combined with a world class molecular genetics lab.

Our AVIAN group is also one of the few labs in the world which keep a breeding population of red junglefowl, the wild ancestor to the chicken. Thus we are able to do comparisons directly to a wild ancestor, as well as breed crosses between modern chickens and their wild ancestors for genetic experiments.


National and International Research Collaborations

I have made it a point to always maintain cordial relations with numerous researchers and over the years I have managed to build a very extensive research network. Together with Professor Linda Keeling at SLU, I currently coordinate the Center of Excellence in Animal Welfare Science, a nationwide research network. The AVIAN group is part of Linköpings University's System Neurobiology Network and we have a number of ongoing collaborations with researchers at the Faculty of Medicine and Health Sciences. This has generated a number of emerging projects towards human applications and given us unique inroads towards human-centric research.

Sample collaborations

  • Professor Linda Keeling, SLU – animal welfare science.
  • Professor Leif Andersson, Uppsala University – genetics and genomics.
  • Professor Jonas Bergquist, Uppsala University – hormone measurements.
  • Professor Elena Jazin, Uppsala University – behaviour epigenetics.



Academic degrees, positions, and achievements

  • PhD Applied Ethology, Swedish University of Agricultural Sciences, 1983
  • Docent in Ethology, Swedish University of Agricultural Sciences, 1985
  • Personal professorship in Ethology, Swedish University of Agricultual Sciences, 1988
  • Guest professor, Linköping University, 2002-2005.
  • Professor of Ethology, Linköping University, since 2005
  • Scientific head of the Avian Behavioural Genomics and Physiology group (In total appr. 35-40 people, of which six PI:s, 16 PhD-students, 4 post-docs, 4 technicians, and 5-10 masters-students), since 2010
  • Holder of “professor-contract” since 2008 (yearly funding of 2.2 MKr from Linköping University, granted on grounds of excellence to a number of University professors).

Compleate Curriculum Vitate (PDF)

Publication record

  • Over 150 published peer reviewed papers.
  • 7 single-authored text books in Swedish.
  • 2 edited international text-books.
  • h-index: 42
  • Total number of citations (Web of Science, Sept. 2014): 4500

Invited talks 

More than 20 invited talks at different international conferences, for example: Society for Experimental Biology, Cognition and Evolution, German Ethology Conference, International Society for Applied Ethology Conference, Dutch Ethology Conference

Important national and international assignments

  • Member/chairman of the EU-commision’s Scientific Committee on Animal Health and Animal Welfare, 1994-2003.
  • Member of scientific board for PhD-training school, University of Utrecht, 2001-2004
  • Member of the animal welfare council of the Swedish Agricultural Board, 2004 –2006; 2013 - present
  • Member of Research Council Formas Scientific Board 2007-12
  • Member of Research Council VR scientific panel for international post docs 2013-2015
  • Member of ERC scientific panel for consolidator grants, Life Science 2013-2015



Madlen Stange, Daniel Nunez-Leon, Marcelo R. Sanchez-Villagra, Per Jensen, Laura A. B. Wilson

Morphological variation under domestication: how variable are chickens?

In Royal Society Open Science

Article in journal

Ann-Sofie Sundman, Mia Persson, Anna Grozelier, Lise-Lotte Halldén, Per Jensen, Lina Roth

Understanding of human referential gestures is not correlated to humandirectedsocial behaviour in Labrador retrievers and German shepherd dogs

In Applied Animal Behaviour Science

Article in journal

Martin Johnsson, Rie Henriksen, Jesper Fogelholm, Andrey Höglund, Per Jensen, Dominic Wright

Genetics and Genomics of Social Behavior in a Chicken Model

In Genetics

Article in journal

Beatrix Agnvall, Johan Bélteky, Rebecca Katajamaa, Per Jensen

Is evolution of domestication driven by tameness? A selective review with focus on chickens

In Applied Animal Behaviour Science

Article in journal

Henry Buller, Harry Blokhuis, Per Jensen, Linda Keeling

Towards Farm Animal Welfare and Sustainability

In Animals

Article, review/survey

Martin Johnsson, Rie Henriksen, Andrey Höglund, Jesper Fogelholm, Per Jensen, Dominic Wright

Genetical genomics of growth in a chicken model

In BMC Genomics

Article in journal

Amir Fallahsharoudi, Pia Løtvedt, Johan Beltéky, Jordi Altimiras, Per Jensen

Changes in pituitary gene expression may underlie multiple domesticated traits in chickens.

In Heredity

Article in journal

Johan Bélteky, Beatrix Agnvall, Lejla Bektic, Andrey Höglund, Per Jensen, Carlos Guerrero Bosagna

Epigenetics and early domestication: differences in hypothalamic DNA methylation between red junglefowl divergently selected for high or low fear of humans

In Genetics Selection Evolution

Article in journal


Amir Fallahshahroudi, Neil de Kock, Martin Johnsson, Lejla Bektic, S J Kumari A Ubhayasekera, Jonas Bergquist, Dominic Wright, Per Jensen

Genetic and Targeted eQTL Mapping Reveals Strong Candidate Genes Modulating the Stress Response During Chicken Domestication.

In G3

Article in journal

Johan Beltéky, Beatrix Eklund, Per Jensen

Gene expression of behaviorally relevant genes in the cerebral hemisphere changes after selection for tameness in Red Junglefowl.


Article in journal

Beatrix Agnvall, Johan Bélteky, Per Jensen

Brain size is reduced by selectionfor tameness in Red Junglefowl–correlated effects in vital organs

In Scientific Reports

Article in journal

Fábio Pértille, Margrethe Brantsæter, Janicke Nordgreen, Luiz Lehmann Coutinho, Andrew M Janczak, Per Jensen, Carlos Guerrero Bosagna

DNA methylation profiles in red blood cells of adult hens correlatewith their rearing conditions

In Journal of Experimental Biology

Article in journal

Josefina Zidar, Alexandra Balogh, Anna Favati, Per Jensen, Olof Leimar, Hanne Lovlie

A comparison of animal personality and coping styles in the red junglefowl

In Animal Behaviour

Article in journal

Josefina Zidar, Enrico Sorato, Ann-Marie Malmqvist, Emelie Jansson, Charlotte Rosher, Per Jensen, Anna Favati, Hanne Løvlie

Early experience affects adult personality in the red junglefowl: a role for cognitive stimulation?

In Behavioural Processes

Article in journal