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  • 101.
    Rubin, Carl-John
    et al.
    Department of Medical Sciences Uppsala University.
    Brändström, Helena
    Department of Medical Sceinces Uppsala University.
    Wright, Dominic
    Department of Medical Biochemistry and Microbiology Uppsala University.
    Kerje, Susanne
    Department of Medical Biochemistry and Microbiology Uppsala University.
    Gunnarsson, Ulrika
    Department of Medical Biochemistry and Microbiology Uppsala University.
    Schütz, Karin
    AgResearch Animal Behaviour and Welfare, New Zealand.
    Fredriksson, Robert
    Department of Neuroscience Uppsala University.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Zoology . Linköping University, The Institute of Technology.
    Andersson, Leif
    Department of Medical Biochemistry and Microbiology Uppsala University.
    Ohlsson, Claes
    Department of Internal Medicine The Sahlgrenska University Hospital, Göteborg.
    Mallmin, Hans
    Department of Surgical Sciences Uppsala University Hospital, Uppsala.
    Larsson, Sune
    Department of Surgical Sciences Uppsala University Hospital, Uppsala.
    Kindmark, Andreas
    Department of Medical Sciences Uppsala University.
    Quantitative trait loci for BMD and bone strength in an intercross between domestic and wildtype chickens2007In: Journal of Bone and Mineral Research, ISSN 0884-0431, E-ISSN 1523-4681, Vol. 22, no 3, p. 375-384Article in journal (Refereed)
    Abstract [en]

    With chicken used as a model species, we used QTL analysis to examine the genetic contribution to bone traits. We report the identification of four QTLs for femoral traits: one for bone strength, one for endosteal circumference, and two affecting mineral density of noncortical bone. INTRODUCTION: BMD is a highly heritable phenotype, governed by elements at numerous loci. In studies examining the genetic contribution to bone traits, many loci have been identified in humans and in other species. The goal of this study was to identify quantitative trait loci (QTLs) controlling BMD and bone strength in an intercross between wildtype and domestic chickens. MATERIALS AND METHODS: A set of 164 markers, covering 30 chromosomes (chr.), were used to genotype 337 F2-individuals from an intercross of domesticated white Leghorn and wildtype red junglefowl chicken. DXA and pQCT were used to measure BMD and bone structure. Three-point bending tests and torsional strength tests were performed to determine the biomechanical strength of the bone. QTLs were mapped using forward selection for loci with significant marginal effects. RESULTS: Four QTLs for femoral bone traits were identified in QTL analysis with body weight included as a covariate. A QTL on chr. 1 affected female noncortical BMD (LOD 4.6) and is syntenic to human 12q21-12q23. Also located on chr. 1, a locus with synteny to human 12q13-14 affected endosteal circumference (LOD 4.6). On chr. 2, a QTL corresponding to human 5p13-p15, 7p12, 18q12, 18q21, and 9q22-9q31 affected BMD in females; noncortical (LOD 4.0) and metaphyseal (LOD 7.0) BMD by pQCT and BMD by DXA (LOD 5.9). A QTL located on chr. 20 (LOD 5.2) affected bone biomechanical strength and had sex-dependent effects. In addition to the significant QTLs, 10 further loci with suggestive linkage to bone traits were identified. CONCLUSIONS: Four QTLs were identified: two for noncortical BMD, one for endosteal circumference, and one affecting bone biomechanical strength. The future identification of genes responsible for these QTLs will increase the understanding of vertebrate skeletal biology.   

  • 102. Schutz, KE
    et al.
    Kerje, Susanne
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Jacobsson, L
    Forkman, B
    Carlborg, O
    Andersson, L
    Jensen, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Zoology .
    Major growth QTLs in fowl are related to fearful behavior: possible genetic links between fear responses and production traits in a red junglefowl x White Leghorn intercross2004In: Behavior Genetics, ISSN 0001-8244, E-ISSN 1573-3297, Vol. 34, no 1, p. 121-130Article in journal (Refereed)
    Abstract [en]

    The aim of this work was to study fear responses and their relation to production traits in red junglefowl (Gallus gallus spp.), White Leghorn (Gallus domesticus), and their F-2-progeny. Quantitative trait locus (QTL) analyses were performed for behavioral traits to gain information about possible genetic links between fear-related behaviors and production. Four behavioral tests were performed that induce different levels of acute fear (open field [OF], exposure to a novel object, tonic immobility, and restraint). Production traits, that is, egg production, sexual maturity (in females), food intake, and growth, were measured individually. A genome scan using 105 microsatellite markers was carried out to identify QTLs controlling the traits studied. In the OF and novel object tests (NO), Leghorns showed less fear behavior than junglefowl, whereas junglefowl behaved less fearfully in the tonic immobility test (TI) and were more active in the restraint test. In the F-2 progeny, only weak phenotypic associations were found between production traits and fear behavior. A significant QTL for TI duration was found on chromosome 1 that coincided with a QTL for egg weight and growth in the same animals. Another QTL for NO in males coincided with another major growth QTL. These two known growth QTLs affected a wide range of reactions in different tests. Several other significant and suggestive QTLs for behavioral traits related to fear were found. These QTLs did not coincide with QTLs for production traits, indicating that these fear variables may not be genetically linked to the production traits we measured here. The results show that loci affecting important production traits are located in the same chromosomal region as loci affecting different fear-related behaviors.

  • 103.
    Väisänen, Johanna
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Håkansson, Jennie
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Social interactions in Red Junglefowl (Gallus gallus) and White Leghorn layers in stable groups and after re-grouping2005In: British Poultry Science, ISSN 0007-1668, E-ISSN 1466-1799, Vol. 46, no 2, p. 156-168Article in journal (Refereed)
    Abstract [en]

    1. Although social behaviour is a major factor affecting the coping of poultry in production environments little is known about how it has been affected by intensive selection processes in fowl. We attempted to clarify selection effects on overall repertoire and occurrence of different social behaviours as well as on aggressive responses to re-grouping with unfamiliar birds by comparing high-producing White Leghorn layers to wild type Red Junglefowl.

    2. In the first experiment we observed 8 stable mixed sex groups/breed each consisting of four 24-week-old birds previously familiar to each other. During 9 consecutive days, a wide range of social signals, sexual and aggressive interactions as well as spacing behaviour and activity were recorded over a 12-h photoperiod.

    3. In the second experiment, starting at 19 weeks of age, 16 single sex groups of three birds from each breed were formed by mixing unfamiliar individuals. Aggressive behaviours were recorded 0, 5, 24 and 48 h after re-grouping.

    4. Results from the stable groups indicated that the repertoire of social behaviours has been preserved during selection with few changes in frequencies and intensities. However, Leghorns showed a more cohesive spacing pattern than junglefowl.

    5. In the second experiment, aggressive activity was higher immediately and after 24 h following re-grouping in Leghorns, but there was a drop in the aggressiveness at 5 h to the same level as junglefowl. We suggest that this may indicate poorer social learning capacity with a weaker ability to cope with group disruptions compared to the ancestral breed.

  • 104.
    Väisänen, Johanna
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Responses of young red jungle fowl (Gallus gallus) and white leghorn layers to familiar and unfamiliar social stimuli2004In: Poultry Science, ISSN 0032-5791, E-ISSN 1525-3171, Vol. 83, no 3, p. 335-343Article in journal (Refereed)
    Abstract [en]

    Social preferences of familiar over unfamiliar social stimuli in chicks may be used to measure sociality, a characteristic important for the welfare of poultry in commercial production. We studied social preferences and reaction to strangers in young White Leghorns and red jungle fowl (Gallus gallus) in 3 tests. All chicks were raised and housed in 2 groups of 34 individuals per breed. At 24 to 29 d of age 38 chicks per breed were tested in 2 runway tests. In the first, chicks had a free choice between familiar and unfamiliar breed members, and in the second the choice was between unfamiliar chicks of their own breed and the other breed. On d 41 to 42, spacing and agonistic interactions of 28 pairs of chicks per breed (in half of the pairs, chicks were unfamiliar to each other) were observed in an open field for 10 min (pair test). In the first runway test, clear preference for familiar chicks and avoidance of unfamiliar social stimuli was found only in Leghorns, whereas both breeds showed a preference for their own breed members in the second runway test. Affiliation to the familiar breed, however, was more pronounced in Leghorns. In the pair test, Leghorns were significantly more involved in agonistic interactions than wild-type chicks. Avoidance of unfamiliar and preference for familiar conspecifics might suggest a weaker capacity of Leghorns to cope with novel social and environmental stimuli, which might have implications for the welfare of the birds in production environments when encountering unfamiliar individuals.

  • 105.
    Väisänen, Johanna
    et al.
    Department of Animal Environment and Health, Section of Ethology, Swedish University of Agricultural Sciences, Skara, Sweden.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Social versus exploration and foraging motivation in young red junglefowl (Gallus gallus) and White Leghorn layers2003In: Applied Animal Behaviour Science, ISSN 0168-1591, E-ISSN 1872-9045, Vol. 84, no 2, p. 139-158Article in journal (Refereed)
    Abstract [en]

    Social coherence tendency is an important behavioural characteristic in young fowl related to an underlying social motivation that can be modified by breeding. Our aim was to investigate if selection for productive traits in a certain White Leghorn layer strain has influenced different components of social motivation compared to the ancestor, red junglefowl. From both breeds, 29 chicks were tested between 4 and 7 weeks of age in four behavioural tests designed to study social motivation. A runway test was used to measure social reinstatement behaviour. Social coherence tendency versus foraging motivation was measured in both novel and familiar environments following 0 and 3 h food deprivation. The novel environment was an L-shaped social versus foraging arena and the familiar environment was identical to the chicks’ home pens. Both included stimulus birds in a box and food at opposite ends of the test arenas. Furthermore, spacing behaviour of groups consisting of three chicks was observed in a novel pen. The runway test revealed a stronger social affiliation in junglefowl when the social contact had first been reinstated. In the social versus foraging arena, junglefowl moved more whereas Leghorns spent more time immobile. These differences were greater with 3 h food deprivation. Deprivation and breed had a significant interaction resulting in more time spent feeding by junglefowl but not by Leghorns. Contrary to this, in the familiar pen, Leghorns responded to deprivation by feeding more and keeping longer distance to the stimulus birds than junglefowl. In the novel pen, Leghorn chicks had shorter nearest neighbour distances than junglefowl. The results indicate that the adaptability of the birds to their social and physical environment may have been influenced by means of selection for increased production capacity. Leghorns from the studied strain may have greater problems in adapting to a new environment.

  • 106.
    Väisänen, Johanna
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology.
    Kerje, Susanne
    Department of Medical Biochemistry and Microbiology, Uppsala University, Sweden.
    Gunnarsson, Ulrika
    Department of Medical Biochemistry and Microbiology, Uppsala University, Sweden.
    Andersson, Leif
    Department of Medical Biochemistry and Microbiology, Uppsala University, Sweden.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Sociality in a White Leghorn x Red Junglefowl (Gallus gallus) cross affected by a major growth QTLManuscript (preprint) (Other academic)
    Abstract [en]

    Comparisons between the chicken ancestor, red junglefowl, and domesticated White Leghorn layers have shown that junglefowl chicks are more explorative in novel environments while layers tend to immobilize and stay closer to social stimuli. We aimed at studying if these differences between populations are connected to QTL, Growth1, identified earlier on chromosome 1, which is associated with several production and domestication related traits in fowl, for example growth. To narrow down the size of the QTL, a backcross was produced, using F3 Leghorn/junglefowl intercross males segregating along the QTL and Leghorn females. The offspring were genotyped at nine different marker positions along the QTL. The genotype at each marker position could be either heterozygous junglefowl/Leghorn or homozygous Leghorn. Ninety-two backcross chicks reared as one batch were tested after 3-h food deprivation in an L-shaped maze for 10-min. The test was the same as previously used for the parental chicks. The chicks had a free choice between food and social companions at opposite ends of the test arena. The results revealed that two chromosomal areas in the Growth1 QTL region were associated with the behavioral variables in the test. Furthermore, the differences between the two alternative marker allele genotypes closely resembled those seen between the parental stocks earlier: the heterozygous chicks behaved as junglefowl while homozygous ones acted more like Leghorns. The tendencies for the chicks to immobilize and start feeding in the test were linked to MCW106, whereas social motivation had a strong association to three adjacent markers. MCW010. UG0006 and UG0002. These results support previous studies, suggesting that this QTL has an important role in controlling domestication related traits in fowl.

  • 107.
    Väisänen, Johanna
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Lindqvist, Christina
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Co-segregation of behaviour and production related traits in an F3 intercross between red junglefowl and White Leghorn laying hens2005In: Livestock Production Science, ISSN 0301-6226, E-ISSN 1872-6070, Vol. 94, no 3, p. 149-158Article in journal (Refereed)
    Abstract [en]

    In poultry breeding, selection for production traits may cause side-effects on the physiology and behaviour of the birds with a potential influence on animal welfare. Genetic associations between phenotypic traits can be studied in an intercross of two divergent breeds. In advanced generations, traits controlled by the same genes or by genes located close to each other will co-segregate. Our aim was to study if behavioural styles expressed by red junglefowl (n=26) and White Leghorn (n=26) in a social vs. exploration motivation test as well as breed-differences in contrafreeloading (CFL), an energy demanding feeding strategy, would co-segregate with production related traits in their F3 intercross progeny (n=78). The results revealed Leghorns to maintain closer social contact in the test, whereas junglefowl, which according to previous studies have also a higher degree of CFL, were more active and explorative. Furthermore, these behavioural differences correlated with several production related traits, such as growth and residual feed intake (RFI), in the F3 generation. F3 birds with higher levels of production related traits behaved in a fashion resembling Leghorns more than junglefowl. Both in parental animals and the F3 birds, the above effects were clearest among females. The results, thereby, suggest that selection for high production in fowl may simultaneously have side-effects on sociality and foraging. This could further influence the general capacity of birds to cope with environmental challenges such as exploring a novel environment. The genetic mechanisms underlying this co-segregation remain to be investigated.

  • 108.
    Willems, Els
    et al.
    KU Leuven, Department of Biosystems, Laboratory of Livestock Physiology, Kasteelpark Arenberg 30 box 2456, 3001 Leuven, Belgium.
    Guerrero-Bosagna, Carlos
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Decuypere, Eddy
    KU Leuven, Department of Biosystems, Laboratory of Livestock Physiology, Kasteelpark Arenberg 30 box 2456, 3001 Leuven, Belgium.
    Janssens, Steven
    KU Leuven, Department of Biosystems, Research Group Livestock Genetics, Kasteelpark Arenberg 30 box 2456, 3001 Leuven, Belgium.
    Buyse, Johan
    KU Leuven, Department of Biosystems, Laboratory of Livestock Physiology, Kasteelpark Arenberg 30 box 2456, 3001 Leuven, Belgium.
    Buys, Nadine
    KU Leuven, Department of Biosystems, Research Group Livestock Genetics, Kasteelpark Arenberg 30 box 2456, 3001 Leuven, Belgium.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Everaert, Nadia
    4University of Liège, Gembloux Agro-Bio Tech, Precision Livestock and Nutrition Unit, Passage des Déportés 2, 5030 Gembloux, Belgium.
    Differential Expression of Genes and DNA Methylation associated with Prenatal Protein Undernutrition by Albumen Removal in an avian model2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6Article in journal (Refereed)
    Abstract [en]

    Previously, long-term effects on body weight and reproductive performance have been demonstrated in the chicken model of prenatal protein undernutrition by albumen removal. Introduction of such persistent alterations in phenotype suggests stable changes in gene expression. Therefore, a genome-wide screening of the hepatic transcriptome by RNA-Seq was performed in adult hens. The albumen-deprived hens were created by partial removal of the albumen from eggs and replacement with saline early during embryonic development. Results were compared to sham-manipulated hens and non-manipulated hens. Grouping of the differentially expressed (DE) genes according to biological functions revealed the involvement of processes such as 'embryonic and organismal development' and 'reproductive system development and function'. Molecular pathways that were altered were 'amino acid metabolism', 'carbohydrate metabolism' and 'protein synthesis'. Three key central genes interacting with many DE genes were identified: UBC, NR3C1, and ELAVL1. The DNA methylation of 9 DE genes and 3 key central genes was examined by MeDIP-qPCR. The DNA methylation of a fragment (UBC_3) of the UBC gene was increased in the albumen-deprived hens compared to the non-manipulated hens. In conclusion, these results demonstrated that prenatal protein undernutrition by albumen removal leads to long-term alterations of the hepatic transcriptome in the chicken.

  • 109.
    Wiren, Anders
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Zoology. Linköping University, The Institute of Technology.
    Gunnarsson, U
    Uppsala University.
    Andersson, L
    Uppsala University.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Zoology. Linköping University, The Institute of Technology.
    Domestication-related genetic effects on social behavior in chickens - Effects of genotype at a major growth quantitative trait locus2009In: Poultry Science, ISSN 0032-5791, E-ISSN 1525-3171, Vol. 88, no 6, p. 1162-1166Article in journal (Refereed)
    Abstract [en]

    Domestication is an evolutionary process in which animals become adapted to a life in close proximity to humans. There are typically specific selection pressures associated with this, including living in larger social groups than their wild ancestors. We hypothesized that the genotype at a major growth QTL could affect aspects of social behavior in chickens as well. We performed social behavior tests in red junglefowl (RJF) and White Leghorn (WL) chickens and in chickens from a selected advanced intercross line (SAIL) between RJF and WL, selected for different genotypes at a microsatellite marker locus within the QTL region. Four-week-old pure WL inspected strangers significantly more than pure RJF. Male 4-wk-old SAIL birds, homozygous for the WL allele at the marker locus, differed from those with RJF alleles in a similar way as the pure WL differed from RJF. Furthermore, 155- to 170-d-old male SAIL birds homozygous for the WL allele at the marker locus were less aggressive to unfamiliar conspecifics in a dominance test. The results suggest that domestication has caused changes in social behavior, which, in males, may partly depend on variations in the genotype at the growth QTL where the avian homolog of the arginine vasopressin receptor 1a (AVPR1a) is located. This gene is therefore one of several putative candidate genes for future research.

  • 110.
    Wirén, Anders
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Zoology. Linköping University, The Institute of Technology.
    Wright, Dominic
    Linköping University, Department of Physics, Chemistry and Biology, Zoology. Linköping University, The Institute of Technology.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Zoology. Linköping University, The Institute of Technology.
    Domestication-related variation in social preferences in chickens is affected by genotype on a growth QTL2013In: Genes, Brain and Behavior, ISSN 1601-1848, E-ISSN 1601-183X, Vol. 12, no 3, p. 330-337Article in journal (Refereed)
    Abstract [en]

    A growth-related QTL on chicken chromosome 1 has previously been shown to influence domestication behaviour in chickens. In this study, we used Red Junglefowl (RJF) and White Leghorn (WL) as well as the intercross between them to investigate whether stress affects the way birds allocate their time between familiar and unfamiliar conspecifics in a social preference test (‘social support seeking’), and how this is related to genotype at specific loci within the growth QTL. Red Junglefowl males spent more time with unfamiliar chickens before the stressful event compared to the other birds, whereas all birds except WL males tended to spend less time with unfamiliar ones after stress. A significant QTL locus was found to influence both social preference under undisturbed circumstances and social support seeking. The WL allele at this QTL was associated not only with a preference for unfamiliar individuals but also with a shift towards familiar ones in response to stress (social support seeking). A second, suggestive QTL also affected social support seeking, but in the opposite direction; the WL allele was associated with increased time spent with unfamiliar individuals. The region contains several possible candidate genes, and gene expression analysis of a number of them showed differential expression between RJF and WL of AVPR2 (receptor for vasotocin), and possibly AVPR1a (another vasotocin receptor) and NRCAM (involved in neural development) in the lower frontal lobes of the brains of RJF and WL animals. These three genes continue to be interesting candidates for the observed behavioural effects.

  • 111.
    Wirén, Anders
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Zoology. Linköping University, The Institute of Technology.
    Wright, Dominic
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Zoology. Linköping University, The Institute of Technology.
    Effects of a Chicken Growth QTL on Behaviour are due to Linkage rather than PleiotropyManuscript (preprint) (Other academic)
    Abstract [en]

    earlier studies, we have found pleiotropic effects of a growth QTL in chickens on behavioural traits that have changed as a result of domestication. In this study we performed a) a refined analysis of the QTL in an advanced intercross line between Red Junglefowl (RJF) and White Leghorn layers (WL) to investigate if different behavioural and physiological traits are associated with different regions of the QTL, and b) brain gene expression analysis (using qRT-PCR) in RJF and WL, comparing the expression between breeds of a number of genes within the growth QTL that may be considered candidates for affecting behavioural traits. The refined QTL analysis was performed on 62 birds from a selected line corresponding to the F7 generation of an RJF×WL intercross (SAIL). The gene expression analysis was performed on 12 RJF and 10 WL birds. In addition to recording of weight data, the SAIL birds were exposed to a behavioural test measuring aspects of sociality and emotionality. The QTL analysis found a significant association between body weight at 8 days of age and a 1.7 MB region in the QTL, and a suggestive association between emotionality related behaviours and a different part, 7.5 MB large, of the QTL. The gene expression analysis showed differential expression of AVPR2 (receptor for vasotocin), possibly AVPR1a (another vasotocin receptor) and NRCAM (involved in neural development) in the lower frontal lobes of the brains of RJF and WL birds. It therefore seems that linkage of several different genes affecting different traits, rather than pleiotropy of one or a few, may explain the many effects of this QTL, and that AVPR2, AVPR1a and NRCAM cannot be discarded as candidate genes for the observed effects.

  • 112.
    Wirén, Anders
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Zoology. Linköping University, The Institute of Technology.
    Wright, Dominic
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Zoology. Linköping University, The Institute of Technology.
    Social preference and support seeking in chickens is related to genotype on a growth QTLManuscript (preprint) (Other academic)
    Abstract [en]

    A growth related QTL on chicken chromosome 1 has previously been shown to influence both emotionality and social behaviour in an intercross line between Red Junglefowl (RJF, ancestor of all domestic chicken breeds) and the domesticated White Leghorn layer (WL). Social support from a familiar animal has been shown to attenuate stress response in other species. In this study we therefore used the RJF×WL intercross line to investigate whether stress in the form of physical restraint affects the way birds allocate their time between familiar and unfamiliar conspecifics in a social preference test. A refined QTL study was performed, focussing on the region of the previously reported growth QTL to find possible loci affecting traits related to social preference and social support. A significant QTL was found to influence both social preference under undisturbed circumstances and social support seeking in response to stress. A WL allele at this QTL was associated with a preference for unfamiliar individuals but also with a shift towards familiar ones in response to stress. A second, suggestive, QTL also affected social support seeking, but in the opposite direction; a WL allele was associated with seeking social support from unfamiliar individuals. It is difficult to speculate on causative genes, but it is worth noting that AVPR1a (known for effects on social behaviour), AVPR2, NRCAM (related to autism) and GRIP1 (Glutamate Receptor Interacting Protein) are located this chromosomal area.

  • 113.
    Wirén, Anna
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Zoology. Linköping University, The Institute of Technology.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Zoology. Linköping University, The Institute of Technology.
    A growth QTL affects emotionality and sociality in chickens2010In: Behavior Genetics, ISSN 0001-8244, E-ISSN 1573-3297, Vol. 40, no 6, p. 819-819Article in journal (Other academic)
    Abstract [en]

    Domestic animals have long been selected for preferable physiolog-ical traits such as high body weight, fast growth rate, high milk yieldetc. Whether intentional or not, this intense selection has also had sideeffects on the behaviour of animals. Such side effects may be due to pleiotropy of production related genes, or close linkage with genes affecting behaviour. In this study we aimed at investigating the genetic factors responsible for changes in production traits and their correlation to behaviour by comparing birds from an advanced intercross between domestic White Leghorn laying hens and their wild ancestor, the red junglefowl. Social behaviour and emotional reactivity of chickens homozygous for a White Leghorn allele of agrowth QTL (‘‘WL genotype’’) was compared to that of chickens homozygous for the red junglefowl allele (‘‘RJF genotype’’). Young WL genotype birds reacted in a more passive manner to a simulated predator attack and interacted more with their mirror image. When adult, WL genotype birds required more induction attempts before entering tonic immobility than RJF genotype birds. These results suggest that the growth QTL affects a number of domestication related behavioural traits, and may have been a primary target of selection. The QTL contains a multitude of genes, several of which have been linked to social behaviour in other species. Future studies aimed at making a higher resolution phenotypic characterization of the QTL should give more information about which of these genes may be considered candidates for bringing about the behavioural changes associated with animal domestication.

  • 114.
    Wirén, Anna
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Zoology. Linköping University, The Institute of Technology.
    A Growth QTL on Chicken Chromosome 1 Affects Emotionality and Sociality2011In: Behavior Genetics, ISSN 0001-8244, E-ISSN 1573-3297, Vol. 41, no 2, p. 303-311Article in journal (Refereed)
    Abstract [en]

    Domestication of animals, regardless of species, is often accompanied by simultaneous changes in several physiological and behavioral traits (e.g. growth rate and fearfulness). In this study we compared the social behavior and emotional reactivity, as measured in a battery of behavioral tests, of two groups of chickens selected from a common genetic background, an advanced intercross line between the ancestral red junglefowl ("RJF") and the domesticated White Leghorn layer ("WL"). The birds were selected for homozygosity for alternative alleles at one locus (a microsatellite marker), centrally positioned in a previously identified pleiotropic growth QTL on chromosome 1, closely linked to one major candidate gene (AVPR1a) for certain aspects of social behavior. Birds homozygous for the WL allele ("WL genotype") had a modified pattern of social and emotional reactions than birds homozygous for the RJF allele ("RJF genotype"), shown by different scores in a principal components analysis. These results suggest that the growth QTL affects a number of domestication related behavioral traits, and may have been a primary target of selection during domestication. The QTL contains a multitude of genes, several of which have been linked to social behavior (for example the vasotocin receptor AVPR1a targeted in this experiment). Future studies aimed at making a higher resolution genotypic characterization of the QTL should give more information about which of these genes may be considered the strongest candidates for bringing about the behavioral changes associated with animal domestication.

  • 115. Worley, K.
    et al.
    Gillingham, M.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Zoology . Linköping University, The Institute of Technology.
    Kennedy, L.
    Pizzari, Tom
    Linköping University, Department of Physics, Chemistry and Biology, Zoology . Linköping University, The Institute of Technology.
    Kaufman, J.
    Richardson, D.
    Single locus typing of MHC class I and class II B loci in a population of red jungle fowl2008In: Immunogenetics, ISSN 0093-7711, E-ISSN 1432-1211, Vol. 60, no 5, p. 233-247Article in journal (Refereed)
    Abstract [en]

    In species with duplicated major histocompatibility complex (MHC) genes, estimates of genetic variation often rely on multilocus measures of diversity. It is possible that such measures might not always detect more detailed patterns of selection at individual loci. Here, we describe a method that allows us to investigate classical MHC diversity in red jungle fowl (Gallus gallus), the wild ancestor of the domestic chicken, using a single locus approach. This is possible due to the well-characterised gene organisation of the 'minimal essential' MHC (BF/BL region) of the domestic chicken, which comprises two differentially expressed duplicated class I (BF) and two class II B (BLB) genes. Using a combination of reference strand-mediated conformation analysis, cloning and sequencing, we identify nine BF and ten BLB alleles in a captive population of jungle fowl. We show that six BF and five BLB alleles are from the more highly expressed locus of each gene, BF2 and BLB2, respectively. An excess of non-synonymous substitutions across the jungle fowl BF/BL region suggests that diversifying selection has acted on this population. Importantly, single locus screening reveals that the strength of selection is greatest on the highly expressed BF2 locus. This is the first time that a population of red jungle fowl has been typed at the MHC region, laying the basis for further research into the underlying processes acting to maintain MHC diversity in this and other species. © 2008 Springer-Verlag.

  • 116.
    Wright, D
    et al.
    IFM Linköpings universitet.
    Kerje, S
    Dept of Medical Science Uppsala University.
    Lundström, K.
    Dep of Food Science Swedish University of Agricultural Science.
    Babol, J.
    Dep of Food Science Swedish University of Agriculture Science, Uppsala.
    Schultz, K.
    Dep of Animal Environment and Health Swedish University of Agricultural Sciences, Uppsala.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Zoology . Linköping University, The Institute of Technology.
    Andersson, L.
    Dep of Animal Breeding and Genetics Swedish University of Agricultural Sciences, Uppsala.
    Quantitative trait loci analysis of egg and meat production traits in a red junglefowl · White Leghorn cross2006In: Animal Genetics, ISSN 0268-9146, E-ISSN 1365-2052, Vol. 37, no 6, p. 529-534Article in journal (Refereed)
    Abstract [en]

    Egg and production traits are of considerable economic importance in chickens. Using a White Leghorn × red junglefowl F2 intercross, standard production measures of liver weight and colour, egg size, eggshell thickness, egg taste and meat quality were taken. A total of 160 markers covering 29 autosomes and the Z chromosome were genotyped on 175–243 individuals, depending on the trait under consideration. A total of nine significant quantitative trait loci (QTL) and three suggestive QTL were found on chicken chromosomes 1, 2, 4, 5, 7, 8, 10, 12, E47W24 and E22C19W28.

  • 117.
    Wright, Dominic
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology. Edward Grey Institute, Department of Zoology, University of Oxford, Oxford, United Kingdom.
    Kerje, Susanne
    Department of Medical Biochemistry & Microbiology, BMC, Uppsala University, Uppsala, Sweden.
    Brändström, Helena
    Department of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden.
    Schütz, Karin
    Department of Animal Environment & Health, Section of Ethology, Swedish University of Agricultural Sciences, Skara, Sweden.
    Kindmark, Andreas
    Department of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden.
    Andersson, Leif
    Department of Medical Biochemistry & Microbiology, BMC, Uppsala University, Uppsala, Sweden.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Pizzari, Tommaso
    Edward Grey Institute, Department of Zoology, University of Oxford, South Parks Road, Oxford, United Kingdom.
    The genetic architecture of a female sexual ornament2008In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 62, no 1, p. 86-98Article in journal (Refereed)
    Abstract [en]

    Understanding the evolution of sexual ornaments, and particularly that of female sexual ornaments, is an enduring challenge in evolutionary biology. Key to this challenge are establishing the relationship between ornament expression and female reproductive investment, and determining the genetic basis underpinning such relationship. Advances in genomics provide unprecedented opportunities to study the genetic architecture of sexual ornaments in model species. Here, we present a quantitative trait locus (QTL) analysis of a female sexual ornament, the comb of the fowl, Gallus gallus, using a large-scale intercross between red junglefowl and a domestic line, selected for egg production. First, we demonstrate that female somatic investment in comb reflects female reproductive investment. Despite a trade-off between reproductive and skeletal investment mediated by the mobilization of skeletal minerals for egg production, females with proportionally large combs also had relatively high skeletal investment. Second, we identify a major QTL for bisexual expression of comb mass and several QTL specific to female comb mass. Importantly, QTL for comb mass were nonrandomly clustered with QTL for female reproductive and skeletal investment on chromosomes one and three. Together, these results shed light onto the physiological and genetic architecture of a female ornament. 

  • 118.
    Wright, Dominic
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Rubin, C
    Uppsala University.
    Schutz, K
    AgResearch Ltd.
    Kerje, S
    Uppsala University.
    Kindmark, A
    University of Uppsala Hospital.
    Brandstrom, H
    University of Uppsala Hospital.
    Andersson, L
    Uppsala University.
    Pizzari, T
    University of Oxford.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Zoology. Linköping University, The Institute of Technology.
    Onset of Sexual Maturity in Female Chickens is Genetically Linked to Loci Associated with Fecundity and a Sexual Ornament2012In: Reproduction in domestic animals, ISSN 0936-6768, E-ISSN 1439-0531, Vol. 47, no SI, p. 31-36Article in journal (Refereed)
    Abstract [en]

    Onset of sexual maturation is a trait of extreme importance both evolutionarily and economically. Unsurprisingly therefore, domestication has acted to reduce the time to sexual maturation in a variety of animals, including the chicken. In comparison with wild progenitor chickens [the Red Junglefowl (RJF)], domestic layer hens attain maturity approximately 20% earlier. In addition, domestic layers also possess larger combs (a sexual ornament), produce more eggs and have denser bones. A large quantitative trait loci (QTL) analysis (n = 377) was performed using an F2 intercross between a White Leghorn layer breed and a RJF population, with onset of sexual maturity measured and mapped to three separate loci. This cross has already been analysed for comb mass, egg production and bone allocation. Onset of sexual maturity significantly correlated with comb mass, whilst the genetic architecture for sexual maturity and comb mass overlapped at all three loci. For two of these loci, the QTL for sexual maturity and comb mass were statistically indistinguishable from pleiotropy, suggesting that the alleles that increase comb mass also decrease onset of sexual maturity.

  • 119.
    Wright, Dominic
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Zoology . Linköping University, The Institute of Technology.
    Rubin, C-J
    Dept. of Medical Biochemistry and Microbiology, BMC, Uppsala University.
    Martinez Barrio, A
    Dept. of Medical Sciences, Uppsala University Hospital.
    Schütz, K
    Linnaeus Centre for Bioinformatics, Uppsala University.
    Kerje, S
    Dept. of Medical Biochemistry and Microbiology, BMC, Uppsala University.
    Brändström, H
    Dept. of Medical Biochemistry and Microbiology, BMC, Uppsala University.
    Kindmark, A
    Dept. of Medical Biochemistry and Microbiology, BMC, Uppsala University.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Zoology . Linköping University, The Institute of Technology.
    Andersson, L
    Linköping University, Department of Physics, Chemistry and Biology, Zoology . Linköping University, The Institute of Technology.
    The genetic architecture of domestication in the chicken: effects of pleiotropy and linkage2010In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 19, p. 5140-5156Article in journal (Refereed)
    Abstract [en]

    The extent of pleiotropy and epistasis in quantitative traits remains equivocal. In the caseof pleiotropy, multiple quantitative trait loci are often taken to be pleiotropic if theirconfidence intervals overlap, without formal statistical tests being used to ascertain ifthese overlapping loci are statistically significantly pleiotropic. Additionally, the degreeto which the genetic correlations between phenotypic traits are reflected in thesepleiotropic quantitative trait loci is often variable, especially in the case of antagonisticpleiotropy. Similarly, the extent of epistasis in various morphological, behavioural andlife-history traits is also debated, with a general problem being the sample sizes requiredto detect such effects. Domestication involves a large number of trade-offs, which arereflected in numerous behavioural, morphological and life-history traits which haveevolved as a consequence of adaptation to selective pressures exerted by humans andcaptivity. The comparison between wild and domestic animals allows the geneticanalysis of the traits that differ between these population types, as well as being ageneral model of evolution. Using a large F2 intercross between wild and domesticatedchickens, in combination with a dense SNP and microsatellite marker map, bothpleiotropy and epistasis were analysed. The majority of traits were found to segregate in11 tight ‘blocks’ and reflected the trade-offs associated with domestication. These blockswere shown to have a pleiotropic ‘core’ surrounded by more loosely linked loci. Incontrast, epistatic interactions were almost entirely absent, with only six pairs identifiedover all traits analysed. These results give insights both into the extent of such blocks inevolution and the development of domestication itself.

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