Tame Behavior Research Articles

Serum Levels of Cortisol and Testosterone in American Mink (Neogale Vison) Selected for Aggressive and Tame Behavior towards Humans

Serum Levels of Cortisol and Testosterone in American Mink (Neogale Vison) Selected for Aggressive and Tame Behavior towards Humans

HIPPOCAMPAL VOLUME AND THE SPECTRUM OF METABOLITES IN ADULT GRAY RATS (<i>RATTUS NORVEGICUS</i>) SELECTED FOR DIFFERENT ATTITUDES TO HUMANS AND EXPOSED TO SOCIAL DISTURBANCE IN EARLY LIFE

Previous magnetic resonance studies of the dorsal hippocampus of male rats selected for aggressive attitude to humans revealed lower contents of γ-aminobutyric acid (GABA), N-acetylaspartate, and creatine+phosphocreatine and an elevated content of phosphorylethanolamine as compared to males selected for tame behavior. We investigated the influence of early social instability environment on the hippocampal volumes and spectrum neurometabolites in the dorsal hippocampi of adult tame, aggressive, and unselected rats. The experimental social instability included early weaning, subsequent housing in twos till the age of 3 months, a daily replacement of cagemates from days 19 to 25. Animals of the control groups were weaned at the age of 30 days and kept in fours or fives until the age of 3 months. Control aggressive males were inferior to tame in hippocampal volumes, absolute and normalized to individual brain volumes. The early social instability showed no effect on these indices. In the experimental groups, lower content of phosphorylethanolamine and higher content of alanine in the dorsal hippocampus as compared to control animals were recorded only in aggressive rats. This fact may be related to the formerly observed lower level of stress response in these animals. It follows from the results that aggressive rats are more sensitive to social instability conditions. Also, the early instability conditions and selection for aggressive behavior oppositely affect phosphorylethanolamine metabolism and the integral parameters of the metabolic profile in the dorsal hippocampus.

Bayesian localization of CNV candidates in WGS data within minutes

BackgroundFull Bayesian inference for detecting copy number variants (CNV) from whole-genome sequencing (WGS) data is still largely infeasible due to computational demands. A recently introduced approach to perform Forward–Backward Gibbs sampling using dynamic Haar wavelet compression has alleviated issues of convergence and, to some extent, speed. Yet, the problem remains challenging in practice.ResultsIn this paper, we propose an improved algorithmic framework for this approach. We provide new space-efficient data structures to query sufficient statistics in logarithmic time, based on a linear-time, in-place transform of the data, which also improves on the compression ratio. We also propose a new approach to efficiently store and update marginal state counts obtained from the Gibbs sampler.ConclusionsUsing this approach, we discover several CNV candidates in two rat populations divergently selected for tame and aggressive behavior, consistent with earlier results concerning the domestication syndrome as well as experimental observations. Computationally, we observe a 29.5-fold decrease in memory, an average 5.8-fold speedup, as well as a 191-fold decrease in minor page faults. We also observe that metrics varied greatly in the old implementation, but not the new one. We conjecture that this is due to the better compression scheme. The fully Bayesian segmentation of the entire WGS data set required 3.5 min and 1.24 GB of memory, and can hence be performed on a commodity laptop.

Revisiting the famous farm foxes: A psychological perspective.

Five decades ago, Dmitry Belyaev, Lyudmila Trut, and colleagues began a now-famous experiment, selectively breeding foxes based on one criterion: perceived tame behavior. Over generations, the fox population changed in behavior (as predicted) but, intriguingly, also changed markedly in appearance-for example, many had wider mouths, curlier tails, different fur coloring, and floppy ears. These researchers concluded that the morphological changes that appeared in their foxes were a by-product of the researchers' selecting for genetic variants that are implicated both in behavior and in appearance. For decades, scientists have largely accepted this "shared genetic variants" interpretation to fully account for the co-occurrence of behavioral and morphological phenotypes in these foxes and in other domesticated animals. However, several decades of psychological research on human social cognition, human-canine interaction, and canine behavior strongly suggest that such an account may be incomplete. I forward a supplementary perspective, based on psychological research, that the covariation of appearance and behavior among these foxes may be partly an artifact of human psychological processes at play in selection. These processes include humans' tendency to infer individuals' traits based on their physical features; trait inferences, in turn, influence how humans treat those individuals. If accurate, this account bears on our understanding of these famous foxes, human-canine interactions, as well as humans' role in domestication.

Effects of neonatal handling on behavior and the stress response in rats selected for their reaction towards humans

It is known that neonatal handling may cause long-term changes in neurobiological and behavioral phenotypes. The neonatal handling of rats selected for enhanced aggressiveness towards humans (“aggressive” rats of generation 44) significantly mitigates aggression and stress responsiveness. However, the levels of corticosterone in stress in intact aggressive rats of later (70s) generations are lower than in generation 44, which differ little from the corresponding value in “tame” rats, selected in the opposite direction, for the absence of the aggressiveness towards humans. The goal of the present study is to find out whether the decrease in the stress response in aggressive rats at the current stage of selection is accompanied by a decrease in the influence of handling on aggressiveness. Experiments have been conducted with the Norway rat populations of the 75th generation of selection for aggressive and tame behavior, respectively. It has been found that the neonatal handling of aggressive animals causes a significant decrease in aggressiveness, albeit, considerably smaller than in generation 44. In both aggressive and tame rats, the blood corticosterone level under stress returns to the basal level for a longer time than in the corresponding control groups. Neonatal handling decreases the amount of mRNA for the glucocorticoid receptor (GR) in the hippocampus of aggressive rats but does not significantly affect the amount of mRNA for the corticotropin-releasing hormone (CRH) in the hypothalamus. However, in the control groups the level of CRH mRNA recorded in aggressive rats is higher than in tame ones. On the contrary, no differences in the GR mRNA are found between the strains, in contrast to earlier generations. It has been shown that the neonatal handling of pups is beneficial for maternal behavior in tame rats. Thus, the results obtained in generation 75 of selection indicate that the effect of handling on aggressiveness weakens with decreasing stress responsiveness in aggressive rats. This is likely to be related to the changing amount of GR in the hippocampus and stronger glucocorticoid-mediated feedback at the current stage of selection. The minor prolongation of the stress response appears to be related to the stressing component of neonatal handling rather than to changes in maternal care.

The domestication and the brain: forty years after

The domestication of animals was crucial for the civilization evolutionary experiment. The main characteristic of domesticated animal is tame behavior towards man. D.K. Belyaev suggested that the domestication was carried out by man of the Stone Age as unintended selection of nonaggressive animals. This hypothesis was confirmed at the Institute of Cytology and Genetics, Novosibirsk, by unique long-lasting selection of silver foxes, Norway rats and American minks for nonaggressive behavior towards man. The review concentrates on the role of the brain neurotransmitters in the mechanism of animal domestication. Specifically, it describes the effect of selective breeding for nonaggressive behavior on the brain neurotransmitter serotonin (5-HT) system. Our data showed that produced by domestication the conversion of wild, aggressive animal to non-aggressive towards man is associated with changes in the expression of key molecular members determining the brain 5-HT system functioning. Significant difference between aggressive and nonaggressive animals in the 5-HT metabolism, in the expression of principle metabolic enzymes and 5-HT receptors was shown in different species of mammals (silver foxes, Norway rats and American minks). Higher concentration of 5-HT and its metabolite, 5-hydroxyindoleacetic acid, increased activity of the principle enzyme in 5-HT synthesis (tryptophan hydroxylase-2) and decreased activity of the principle enzyme in 5-HT degradation (monoamine oxidase A) was shown in the midbrain of domesticated silver foxes and rats. The expression of the 5-HTA receptor gene, the density and functional activity of 5-HTA receptors in nonaggressive rats were increased. The review provides converging lines of evidence for our hypothesis that the changes in the brain 5-HT contributes to a mechanism underlying correlative patterns of domestication, i.e. changes in the pivotal for stress response and for the reproduction pituitary-adrenal and pituitary-gonadal systems.

Spectra of definite type in waveguide models

We develop an abstract method to identify spectral points of definite type in the spectrum of the operator T 1 ⊗ I 2 + I 1 ⊗ T 2 T_1\otimes I_2 + I_1\otimes T_2 , applicable in particular for non-self-adjoint waveguide type operators with symmetries. Using the remarkable properties of the spectral points of definite type, we obtain new results on realness of weakly coupled bound states and of low lying essential spectrum in the P T \mathcal {P}\mathcal {T} -symmetric waveguide. Moreover, we show that the pseudospectrum has a tame behavior near the low lying essential spectrum and exclude the accumulation of non-real eigenvalues from this part of the essential spectrum. The advantage of our approach is particularly visible when the resolvent of the unperturbed operator cannot be explicitly expressed and most of the mentioned conclusions are extremely hard to prove by direct methods.

Interplay between aggression, brain monoamines and fur color mutation in the American mink.

Domestication of wild animals alters the aggression towards humans, brain monoamines and coat pigmentation. Our aim is the interplay between aggression, brain monoamines and depigmentation. The Hedlund white mutation in the American mink is an extreme case of depigmentation observed in domesticated animals. The aggressive (-2.06 ± 0.03) and tame (+3.5 ± 0.1) populations of wild-type dark brown color (standard) minks were bred during 17 successive generations for aggressive or tame reaction towards humans, respectively. The Hedlund mutation was transferred to the aggressive and tame backgrounds to generate aggressive (-1.2 ± 0.1) and tame (+3.0 ± 0.2) Hedlund minks. Four groups of 10 males with equal expression of aggressive (-2) or tame (+5) behavior, standard or with the Hedlund mutation, were selected to study biogenic amines in the brain. Decreased levels of noradrenaline in the hypothalamus, but increased concentrations of the serotonin metabolite, 5-hydroxyindoleacetic acid and dopamine metabolite, homovanillic acid, in the striatum were measured in the tame compared with the aggressive standard minks. The Hedlund mutation increased noradrenaline level in the hypothalamus and substantia nigra, serotonin level in the substantia nigra and striatum and decreased dopamine concentration in the hypothalamus and striatum. Significant interaction effects were found between the Hedlund mutation and aggressive behavior on serotonin metabolism in the substantia nigra (P < 0.001), dopamine level in the midbrain (P < 0.01) and its metabolism in the striatum (P < 0.05). These results provide the first experimental evidence of the interplay between aggression, brain monoamines and the Hedlund mutation in the American minks.

Effects of neonatal handling on behavior and stress-response in rats selected for reaction towards humans

It is known that neonatal handling may cause longterm changes in neurobiological and behavioral phenotypes. Neonatal handling of rats selected for enhanced aggressiveness towards humans (“aggressive” rats of generation 44) significantly mitigated aggression and stress responsiveness. However, levels of corticosterone in stress in intact aggressive rats of later generations (70s) were lower than in generation 44, which differed little from the corresponding value in “tame” rats, selected in the opposite direction, for the absence of aggressiveness towards humans. The study was conducted with Norway rat populations of the 75th generation of selection for aggressive and tame behavior, respectively. The goal was to find out whether the decrease in stress response in aggressive rats at the current stage of selection was accompanied by a decrease in the influence of handling on aggressiveness. It was found that neonatal handling of aggressive animals caused a significant decrease in aggressiveness, although considerably smaller than in generation 44. In both aggressive and tame rats, the blood corticosterone level at stress was getting back to the basal level for a longer time than in the corresponding control groups. Neonatal handling decreased the amount of mRNA for the glucocorticoid receptor (GR) in the hippocampus of aggressive rats but did not affect significantly the amount of mRNA for the corticotropin-releasing hormone (CRH) in the hypothalamus. However, higher contents of CRH mRNA were recorded in aggressive rats than in tame ones in the control groups. However, no differences in glucocorticoid receptor mRNA were found between the strains in contrast to earlier generations. It was shown that neonatal handling was beneficial for maternal behavior in tame rats. Thus, the results obtained in the 75th generation of selection indicate that the effect of handling on aggressiveness weakens with decreasing stress responsiveness in aggressive rats. This is likely to be related to the changing amount of GR in the hippocampus and stronger glucocorticoidmediated feedback at the current stage of selection. The minor prolongation of the stress response appears to be related to the stressing component of neonatal handling rather than to changes in maternal care.

動物の従順性行動に関する遺伝解析

動物の従順性行動に関する遺伝解析

Selection for behavior and correlation with the macroglobuline and lypoproteine systems in the American mink (Neovison vison)

A population-genetic comparison between mink populations with tame and aggressive behavior was performed. Six allotypes of the Lpm system, the AIM alpha macroglobulin, and two allotypes of the Ld system, a homologue of APOB low-density lipoprotein, were analyzed. The pairwise compared groups differed in markers Lpml, Lpm3, Lpm5, and Lpm10. Alleles with allotypes Lpml and Lpm3 were significantly associated with aggressive behavior, whereas allele Lpm non-10 was associated tame behavior. No statistically significant differences in the frequencies of Ldl and Ld2 allotypes of the Ld low-density lipoprotein system have been found.

Perturbative gravity from gauge theory

Here, we describe a recently conjectured duality between color and kinematics for gauge-theory amplitudes. Whenever this duality is manifest, the integrands of loop-level gravity scattering amplitudes can be obtained from corresponding gauge-theory amplitudes via a double-copy relation. This duality has been used to enormously simplify a number of explicit multiloop supergravity calculations. The results of these computations is that supergravity theories have a surprisingly tame ultraviolet behavior, and in some cases may even be finite. As an example, we summarize a recent calculation showing that half-maximal [Formula: see text] supergravity in four spacetime dimensions is ultraviolet finite at three loops, contrary to previous expectations.

Fox domestication: Molecular mechanisms involved in selection for behavior

Although animal domestication has enjoyed the attention of geneticists and evolutionary biologists since Darwin’s times, the focal question about the genetic basis of this process has not been duly considered. We present some results of experimental modeling of historical domestication in silver foxes (Vulpes vulpes), an object of commercial breeding. Attention is focused on the role of artificial selection in the transformation of the behavior of these animals, which has brought about unique populations of tame and aggressive foxes. Additional resources were developed to analyze the molecular nature of differences in the behavior of these unique foxes: the meiotic map of the fox genome was constructed, informative segregating subpopulations were obtained by crosses of tame and aggressive animals, and the formerly applied method of behavioral phenotype quantification was improved. The integrated behavioral phenotypes (principal components PC1 and PC2) used in the study were obtained by analysis of ethological parameters recorded with a camcorder. The most important result is that the region most closely associated with tame behavior was identified on fox chromosome 12 by QTL interval mapping. The principle significance of this result is strengthened by the fact that the region is similar to the region on dog chromosome 5, presumed to be responsible for the early domestication of wolves and their evolutionary transformation to primitive dogs.

The non-agoutimutation in Norway rats (Rattus norvegicus) selected for behavior

The frequency of aa homozygous descendants was studied in crosses of Aa heterozygous Norway rat (Rattus norvegicus (Berkenhout, 1769)) parents selected for tame and aggressive behavior. First, Aa heterozygotes were obtained in crosses between tame homozygotes for the wild-type allele (AA) and aggressive homozygotes for the non-agouti allele (aa). The most tame and the most aggressive descendants were selected from the progeny of the Aa genotype by using the glove test. Then Aa rats were crossed among tame and among aggressive descendants, and the AA and Aa genotypes of grey descendants were identified by polymerase chain reactions (PCR). The segregation of descendants into the AA, Aa, and aa genotypes was cumulatively analyzed in five generations of selection with regard to the phenotypic manifestation of tame and aggressive behavior in their parents. The frequency of aa descendants in the progeny of mothers with low aggressive behavior scores was less than expected and less than in the progeny of mothers with high aggressive behavior scores.

The role of innate and environmental influences in shaping antipredator behavior of mainland and insular gartersnakes (Thamnophis sirtalis)

Vertebrates inhabiting islands are often characterized by fearlessness and tame behavior. While this relaxation of antipredator behavior has been documented in many species endemic to islands, fewer researchers have examined it in species that occur both in insular and mainland habitats. In addition, the mechanisms underlying this shift in behavior are still poorly known. For this work, antipredator behavior of island and mainland populations of the common gartersnake (Thamnophis sirtalis) was surveyed. Observed differences were explained in terms of innate tendencies and/or environmental influences using both neonates and adults in laboratory experiments designed to tease apart these two underlying mechanisms. While antipredator behavior of adults was positively correlated with the predation pressures associated with capture sites, neonate behavior did not fully reflect this pattern. However, some support for hard-wired antipredator behavior at birth was evident. Plasticity experiments also revealed that environmental factors appear to influence antipredator behavior. Thus, the data presented here suggest that predation pressures play a strong role in shaping the antipredator behavior of island animals and that the resulting behaviors are most likely the result of some combination of both nature and nurture.

Mapping Loci for fox domestication: deconstruction/reconstruction of a behavioral phenotype.

During the second part of the twentieth century, Belyaev selected tame and aggressive foxes (Vulpes vulpes), in an effort known as the "farm-fox experiment", to recapitulate the process of animal domestication. Using these tame and aggressive foxes as founders of segregant backcross and intercross populations we have employed interval mapping to identify a locus for tame behavior on fox chromosome VVU12. This locus is orthologous to, and therefore validates, a genomic region recently implicated in canine domestication. The tame versus aggressive behavioral phenotype was characterized as the first principal component (PC) of a PC matrix made up of many distinct behavioral traits (e.g. wags tail; comes to the front of the cage; allows head to be touched; holds observer's hand with its mouth; etc.). Mean values of this PC for F1, backcross and intercross populations defined a linear gradient of heritable behavior ranging from tame to aggressive. The second PC did not follow such a gradient, but also mapped to VVU12, and distinguished between active and passive behaviors. These data suggest that (1) there are at least two VVU12 loci associated with behavior; (2) expression of these loci is dependent on interactions with other parts of the genome (the genome context) and therefore varies from one crossbred population to another depending on the individual parents that participated in the cross.

White spotting in Norway rats selected for tame behavior

Norway rats Rattus norvegicus selected over many generations for positive response toward humans were used as a model for the analysis of spotting emergence, penetrance and expressivity in animals differing in the manifestation of tame behavior and in their progeny. Behavior scores and spotting patterns of parents were considered. Although nearly all combinations of white spot locations (chest, chest+belly and belly) can be found in the progeny regardless of white spotting pattern in parents, the frequencies of these combinations depend on the spotting pattern in parents. The results of reciprocal crosses in which either mothers or fathers were spotted and their mates were wholly pigmented indicate that the percentage of spotted offspring is larger among the progeny of spotted fathers. The frequency of spotted individuals among rats with behavior scores of 3.0 and 3.5 (i.e. rats approaching the tester's hand in the glove test) was higher than among rats with the behavior score of 2.5 (avoiding the contact). The frequency of white spots in the progeny depended on the mother's behavior scores; spotting was more frequent in the progeny of rats tolerant of handling than in the progeny of rats that avoided taking in hands. Our data indicate that not only the selection for elimination of aggressive response to humans is associated with higher frequencies of white spot emergence but also further increase in the degree of tame behavior still affects genetic systems associated with spotting.

Maternal methyl supplements affect the phenotypic variation of the agouti gene in the offspring of rats with different behavioral types

The effects of selection of agouti rats (with genotype AAHH) on the tame and aggressive behavior and dietary methyl given to females from the eighth day of pregnancy to the fifth day after the birth of the offspring on the intensity of the agouti coat color in the offspring have been studied. The morphometric parameters of hair determining the darkness of the agouti color (the total length of guard hairs, the lengths of their eumelanin end and pheomelanin band, the ratio between the lengths of the eumelanin and pheomelanin portions of the hair, the total length of the awn hairs, and the relative length of their widened “lanceolate” upper end) have been compared. It has been found that selection of agouti rats for aggressive behavior is accompanied by darkening of the coat color compared to tame rats due to an increase in the ratio of the length of the black eumelanin end of the guard hairs to the length of the yellow pheomelanin band. Methyl-containing additives to the diet of females affect the intensity of the agouti coat color in the offsprings with both types of behavior, but to different extents. Aggressive offspring is more sensitive to the mother’s methyl-containing diet: the percentage of animals that are darker than control rats is higher among aggressive animals than among tame ones due to a greater increase in the ratio between dark and light portions of hairs. The possible mechanisms of differences in the phenotypic modifications of coat color in control and experimental agouti rats with different types of behavior are discussed.

Canid genomics: Mapping genes for behavior in the silver fox

Canid genomics: Mapping genes for behavior in the silver fox

Social Cognitive Evolution in Captive Foxes Is a Correlated By-Product of Experimental Domestication

Dogs have an unusual ability for reading human communicative gestures (e.g., pointing) in comparison to either nonhuman primates (including chimpanzees) or wolves . Although this unusual communicative ability seems to have evolved during domestication , it is unclear whether this evolution occurred as a result of direct selection for this ability, as previously hypothesized , or as a correlated by-product of selection against fear and aggression toward humans--as is the case with a number of morphological and physiological changes associated with domestication . We show here that fox kits from an experimental population selectively bred over 45 years to approach humans fearlessly and nonaggressively (i.e., experimentally domesticated) are not only as skillful as dog puppies in using human gestures but are also more skilled than fox kits from a second, control population not bred for tame behavior (critically, neither population of foxes was ever bred or tested for their ability to use human gestures) . These results suggest that sociocognitive evolution has occurred in the experimental foxes, and possibly domestic dogs, as a correlated by-product of selection on systems mediating fear and aggression, and it is likely the observed social cognitive evolution did not require direct selection for improved social cognitive ability.