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Sundman, Ann-Sofie
Publications (2 of 2) Show all publications
Sundman, A.-S. (2019). Dog behaviour: Intricate picture of genetics, epigenetics, and human-dog relations. (Doctoral dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Dog behaviour: Intricate picture of genetics, epigenetics, and human-dog relations
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Dogs, Canis familiaris, share the lives of humans all over the world. That dogs, and the behavior of dogs, are of interest to many is therefore no surprise. In this thesis, the main aim has been to identify factors that affect dogs’ behaviours.

The dog, Canis familiaris, is our first domesticated animal. Since domestication, various types of dogs have developed through adaptation to an environment shared with humans and through our selective breeding, resulting in a unique variation in morphology and behaviour. Although there is an individual variation in the behaviour of dogs, there is also a difference between breeds. Moreover, selection during the last decades has split some breeds into divergent types. Labrador and golden retrievers are divided into a common type, for show and companionship, and a field type, for hunting. By comparing the breed types, we can study the effects of recent selection. In Paper I, we investigate differences in general behavioural traits between Labrador and golden retriever and between common and field type within the two breeds by using results from the standardized behaviour test Dog Mentality Assessment. There were differences between breeds and types for all behavioural traits. However, there was also an interaction between breed and type. Thus, a common/field-type Labrador does not behave like a common/field-type golden retriever. Even though they have been selected for similar traits, the selection has affected the general behavioural traits differently in the two breeds.

In paper II, we were interested in dogs’ human-directed social skills. Dogs have a high social competence when it comes to humans. Two experiments commonly used to study these skills are the problem-solving test, where dogs’ human-directed behaviours when faced with a problem are measured, and the pointing test, where dogs are tested on how well they understand human gestures. We compared the social skills of German shepherds and Labrador retrievers, and of common- and field-type Labradors. Labradors were more successful in the pointing test and German shepherds stayed closer to their owners during the problem solving. Among Labrador types, the field type had more human eye contact than the common type. Importantly, when comparing the two experiments, we found no positive correlations between the problem-solving test and the pointing test, suggesting that the two tests measure different aspects of human-directed social behaviour in dogs.

A previous study has identified two suggestive genetic regions for human-directed social behaviours during the problem-solving test in beagles. In paper III, we show that these SNPs are also associated to social behaviours in Labrador and golden retrievers. Moreover, the Labrador breed types differed significantly in allele frequencies. This indicates that the two SNPs have been affected by recent selection and may have a part in the differences in sociability between common and field type.

The behaviour of dogs cannot simply be explained by genetics, there is also an environmental component. In paper IV, we study which factors that affect long-term stress in dogs. Long-term cortisol can be measured by hair samples. We found a clear synchronization in hair cortisol concentrations between dogs and their owners. Neither dogs’ activity levels nor their behavioural traits affected the cortisol, however, the personality of the owners did. Therefore, we suggest that dogs mirror the stress level of their owners.

The mediator between genes and the environment is epigenetics, and one epigenetic factor is DNA methylation. In paper V, we compared methylation patterns of wolves and dogs as well as dog breeds. Between both wolves and dogs and among dogs there were substantial differences in methylated DNA regions, suggesting that DNA methylation is likely to contribute to the vast variation among canines. We hypothesize that epigenetic factors have been important during domestication and in breed formation.

In this thesis, I cover several aspects on how dogs’ behaviours can be affected, and paint an intricate picture on how genetics, epigenetics, and human-dog relations forms dog behaviour.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2019. p. 49
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1989
National Category
Evolutionary Biology Zoology Behavioral Sciences Biology Genetics
Identifiers
urn:nbn:se:liu:diva-156353 (URN)10.3384/diss.diva-156353 (DOI)9789176850725 (ISBN)
Public defence
2019-05-09, Planck, Fysikhuset, Campus Valla, Linköping, 09:15 (English)
Opponent
Supervisors
Available from: 2019-04-17 Created: 2019-04-17 Last updated: 2019-04-17Bibliographically approved
Ericsson, M., Henriksen, R., Bélteky, J., Sundman, A.-S., Shionoya, K. & Jensen, P. (2016). Long-Term and Transgenerational Effects of Stress Experienced during Different Life Phases in Chickens (Gallus gallus). PLoS ONE, 11(4), Article ID e0153879.
Open this publication in new window or tab >>Long-Term and Transgenerational Effects of Stress Experienced during Different Life Phases in Chickens (Gallus gallus)
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2016 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 4, article id e0153879Article in journal (Refereed) Published
Abstract [en]

Stress in animals causes not only immediate reactions, but may affect their biology for long periods, even across generations. Particular interest has been paid to perinatal stress, but also adolescence has been shown to be a sensitive period in mammals. So far, no systematic study has been performed of the relative importance of stress encountered during different life phases. In this study, groups of chickens were exposed to a six-day period of repeated stress during three different life phases: early (two weeks), early puberty (eight weeks) and late puberty (17 weeks), and the effects were compared to an unstressed control group. The short-term effects were assessed by behaviour, and the long-term and transgenerational effects were determined by effects on behavior and corticosterone secretion, as well as on hypothalamic gene expression. Short-term effects were strongest in the two week group and the eight week group, whereas long-term and transgenerational effects were detected in all three stress groups. However, stress at different ages affected different aspects of the biology of the chickens, and it was not possible to determine a particularly sensitive life phase. The results show that stress during puberty appears to be at least equally critical as the previously studied early life phase. These findings may have important implications for animal welfare in egg production, since laying hens are often exposed to stress during the three periods pinpointed here.

Place, publisher, year, edition, pages
Plos One, 2016
National Category
Developmental Biology Cell Biology
Identifiers
urn:nbn:se:liu:diva-127492 (URN)10.1371/journal.pone.0153879 (DOI)000374565100026 ()27105229 (PubMedID)
Funder
Swedish Research Council, 621-2011-4731 (PJ)Swedish Research Council Formas, 221-2011-1088 (PJ)EU, European Research Council, 322206 (PJ)
Note

Funding agencies: Swedish Research Council [621-2011-4731]; Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning [221-2011-1088]; European Research Council [322206]

Available from: 2016-04-28 Created: 2016-04-28 Last updated: 2017-11-30Bibliographically approved
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