Genes, dopamine pathways, and sociality in primates

Unraveling the complex sequence of molecular, biochemical, and neuronal cascades that transpire between gene action and behavioral phenotypes has been an exceptionally tough scientific nut to crack. The difficulties in connecting the links between genes and behavior have been especially problematic for social phenotypes, including species-typical social structure, in which multiple individuals are involved in interactions, and hence the appropriate behavioral responses are conditional on actions of a partner. Forty years ago, Robert Hinde (1) provided a critical insight into the dissection and analysis of social behavior, in which he argued that the social structure of a particular species is an emergent consequence of the nature, quality, and patterning of social relationships across time. These relationships, in turn, are dictated by the quality and content of social interactions among partners that derive from the social dispositions of the participants in the interaction. Although little was known about the neurobiological substrates of social behavior at the time, Hinde was sufficiently prescient to appreciate that individual differences in the propensity to engage in social behavior must be linked to variation in important and pervasive underlying neurobiological substrates. Furthermore, Hinde recognized that some of this variation would ultimately be tracked to genetic origins. Since 1976, much has been learned about the ways in which genes shape neurotransmitter systems, and this work has highlighted the role of genetic variability in both regulatory and coding regions of multiple genes in producing both individual differences (2⇓–4) and species diversity (5⇓⇓⇓–9) in social behavior. In PNAS, Bergey et al. (10) provide support for Hinde’s proposition, through evidence that genomic regions associated with dopamine (DA) signaling have diverged dramatically in two closely related species of baboons with markedly different social systems, despite a recent evolutionary split between the species

Trinitarian teams : the Trinity\u27s oneness in our midst

https://place.asburyseminary.edu/ecommonsatsdissertations/2140/thumbnail.jp

Hormonal Assessment of Sexual Maturation in Four Captive Lowland Gorilla Males

Monozygotic twins Mosuba and Macombo were born at the Columbus (Ohio) Zoo in 1983. During their first year, weight and skeletal growth indicators were virtually identical. The twins lived together continuously until age 7, when they were permanently separated. Mosuba joined a group of males and elderly, non-breeding females in the Henry Doorly Zoo of Omaha, Nebraska. He sired an infant by artificial insemination at age 12. At age 16, Mosuba had the appearance of a fully mature silverback, with prominent sagittal and nuchal crests and typical large body size, consistent with his age

Marmosets treated with oxytocin are more socially attractive to their long-term mate

Adult male-female bonds are partly characterized by initiating and maintaining close proximity with a social partner, as well as engaging in high levels of affiliative and sociosexual behavior. Oxytocin (OXT), a neuromodulatory nonapeptide, plays a critical role in the facilitation of social bonding and prosocial behavior toward a social partner (Feldman, 2012). However, less attention has been given to whether augmentation of OXT levels in an individual alters others’ perceptions and behavior toward an OXT-treated social partner. We examined social dynamics in well-established male-female pairs of marmoset monkeys (Callithrix jacchus) in which one member of the pair was administered an intranasal OXT agonist, an OXT antagonist (OXTA), or saline. OXT treatment did not alter the expression of affiliative toward anuntreated partner. However, OXT did significantly influence the expression of proximity and grooming behavior with a treatedpartner, as a function of OXT treatment and sex. Female interest in initiating and maintaining proximity with a pair-mate was altered by OXT treatment. Untreated female marmosets departed from their saline-treated partner more frequently than they approached them, as indicated by a low proximity index score. However, when males received an intranasal OXT agonist they had a significantly increased proximity index score relative to saline, indicating that their untreated partner approached them more often than they departed from them). Saline-treated females initiated and received equivalent levels of grooming behavior. However, when female marmosets were treated with an OXT agonist their untreatedpartner groomed them proportionately more often, for a greater total duration, and for more time per bout, than they initiated grooming behavior. These results suggest that intranasal OXT altered male and female marmosets’ stimulus properties in such a way as to increase the amount of grooming behavior that females received from their long-term mate, as well as increase female interest in initiating and maintaining proximity with their long-term mate. Furthermore, these results support the notion that central OXT activity plays an important neuromodulatory role in the maintenance of long-lasting male-female relationships

Introduction: Fear and Loathing of Evolutionary Psychology in the Social Sciences

When one looks at the intellectual landscape of the modern university, at the scholarly and scientific interests of its faculty, the panorama is seamless. There are no discontinuities. The interests of physicists transmogrify into those of chemists, those of chemists into those of biologists, and so on. The lines, the divisions, between departments have been created out of administrative, not intellectual, necessity

Molecular Variation in \u3ci\u3eAVP\u3c/i\u3e and \u3ci\u3eAVPR1a\u3c/i\u3e in New World Monkeys (Primates, Platyrrhini): Evolution and Implications for Social Monogamy

The neurohypophysial hormone arginine vasopressin (AVP) plays important roles in fluid regulation and vascular resistance. Differences in AVP receptor expression, particularly mediated through variation in the noncoding promoter region of the primary receptor for AVP (AVPR1a), may play a role in social phenotypes, particularly social monogamy, in rodents and humans. Among primates, social monogamy is rare, but is common among New World monkeys (NWM). AVP is a nonapeptide and generally conserved among eutherian mammals, although a recent paper demonstrated that some NWM species possess a novel form of the related neuropeptide hormone, oxytocin. We therefore characterized variation in the AVP and AVPR1a genes in 22 species representing every genus in the three major platyrrhine families (Cebidae, Atelidae and Pitheciidae). For AVP, a total of 16 synonymous substitutions were detected in 15 NWM species. No non-synonymous substitutions were noted, hence, AVP is conserved in NWM. By contrast, relative to the human AVPR1a, 66 predicted amino acids (AA) substitutions were identified in NWM. The AVPR1a N-terminus (ligand binding domain), third intracellular (Gprotein binding domain), and C-terminus were variable among species. Complex evolution of AVPR1a is also apparent in NWM. A molecular phylogenetic tree inferred from AVPR1a coding sequences revealed some consensus taxonomic separation by families, but also a mixed group composed of genera from all three families. The overall dN/dS ratio of AVPR1a was 0.11, but signals of positive selection in distinct AVPR1a regions were observed, including the N-terminus, in which we identified six potential positive selection sites. AA substitutions at positions 241, 319, 399 and 409 occurred uniquely in marmosets and tamarins. Our results enhance the appreciation of genetic diversity in the mammalian AVP/AVPR1a system, and set the stage for molecular modeling of the neurohypophyseal hormones and social behavior in primates

Comparison of cortisol samples in the first two weeks of life in preterm infants

Background: Growing literature on negative childhood stress emphasizes the need to understand cortisol values from varying biomarker samples. Objective: This work aimed to examine cortisol samples for usability, associations, and individual stability in neonates. Subjects: The sample consisted of preterm infants (n=31). Materials and methods: Analyses on cortisol collected from cord blood and from saliva and urine samples on days 1, 7, and 14 included Spearman correlations and paired t-tests. Results: Usability rates were 80.6% (cord blood), 85.9% (saliva), and 93.5% (urine). Salivary and urinary cortisol levels had significant correlation on day 1 only (p=0.004). Significant differences in individual stability of cortisol concentrations existed except in urine on days 1 and 7 and in saliva on days 7 and 14. Conclusions: Usability was highest for urine samples. We found little correlation between cortisol sample levels at each time; individual stability of cortisol concentrations was minimal. Interpretation of cortisol findings in all studies should be performed cautiously

Differences in stress reactivity between zebrafish with alternative stress coping styles

Animals experience stress in a variety of contexts and the behavioural and neuroendocrine responses to stress can vary among conspecifics. The responses across stressors often covary within an individual and are consistently different between individuals, which represent distinct stress coping styles (e.g. proactive and reactive). While studies have identified differences in peak glucocorticoid levels, less is known about how cortisol levels differ between stress coping styles at other time points of the glucocorticoid stress response. Here we quantified whole-body cortisol levels and stress-related behaviours (e.g. depth preference, movement) at time points representing the rise and recovery periods of the stress response in zebrafish lines selectively bred to display the proactive and reactive coping style. We found that cortisol levels and stress behaviours are significantly different between the lines, sexes and time points. Further, individuals from the reactive line showed significantly higher cortisol levels during the rising phase of the stress response compared with those from the proactive line. We also observed a significant correlation between individual variation of cortisol levels and depth preference but only in the reactive line. Our results show that differences in cortisol levels between the alternative stress coping styles extend to the rising phase of the endocrine stress response and that cortisol levels may explain variation in depth preferences in the reactive line. Differences in the timing and duration of cortisol levels may influence immediate behavioural displays and longer lasting neuromolecular mechanisms that modulate future responses