Developmental Continuity Of Individual Differences In Re

该项目通过对恒河猴和其他猴子物种的纵向比较研究来研究灵长类动物的生物行为发育，特别强调描述个体对环境新颖性和挑战的不同行为和生理反应的模式，并确定不同遗传背景的个体在不同的物理和社会环境中长大的长期发育后果。今年完成的几项研究集中在5-羟色胺功能受损的候选基因5-HTT的多态与不同的早期社会经历之间的可能相互作用。我们发表了第一份关于非人类灵长类物种中特定基因-环境相互作用的报告：与那些携带长基因(LL)等位基因的恒河猴相比，携带短等位基因(LS)的恒河猴在中枢5-羟色胺代谢方面表现出缺陷，但只有在它们是在托儿所饲养的情况下才会出现这种缺陷；相比之下，由亲生母亲饲养的LS猴子具有正常的5-羟色胺代谢，这表明母系养育的“缓冲”效应。我们报告了在婴儿期获得的状态控制和视觉定向措施的母系养育的类似缓冲效应。作为一个物种，恒河猴的攻击性是出了名的，相对于其他猕猴(事实上，相对于大多数其他灵长类)；相比之下，巴巴里猕猴的攻击性相对较低，这一点是不寻常的。在过去的一年里，我们能够根据5-HTT基因对一组自由放养的巴巴里猕猴的成员进行分型，并且，与恒河猴的情况不同，我们没有发现有LS或LL等位基因的个体。取而代之的是，所有被采样的巴巴里猕猴都有一种“超长”(XL)等位基因，到目前为止，在不到2%的恒河猴中发现了这种形式。 在过去的一年里，我们还表征了MAO-A受体基因的多态，展示了不同等位基因之间的功能差异，针对这种多态对LCE恒河猴群体进行了基因分型，并开始分析各种行为和生理指标作为遗传状态和早期养育历史的函数。我们的初步分析揭示了幼年期间攻击性行为的显著等位基因x养育历史交互作用：然而，当母亲养育的猴子的“7”等位基因比那些“5”或“6”等位基因的猴子发起更多的攻击性发作时，在苗圃饲养的猴子中发现相反的情况。我们还完成了一项研究，调查了生活在自由放牧的自然主义社会群体中的成年雌性恒河猴的5-羟色胺代谢与冲动和攻击行为指标之间的关系。先前的研究表明，在自由放养的成年雄性恒河猴以及圈养成年雄性和雌性恒河猴中，脑脊液(CSF)中主要的5-羟色胺代谢产物5-HIAA浓度较低与相对较高的危险、冲动行为和社会不适当、暴力攻击(但与低水平、社会适当的优势行为)相关。我们的分析表明，在这些自由放牧的雌性动物中，较低的CSF5-HIAA浓度也与过度危险、冲动的行为有关，但与暴力攻击无关；相反，CSF5-HIAA与社交适当的支配行为之间存在显著的负相关。最后，我们发表了一项研究，考察了在养育的恒河猴婴儿的标准饮食中添加长链必需脂肪酸补充剂的生物行为后果，这有效地提高了他们的血清水平，使其达到由亲生母亲抚养(和哺育)的婴儿的特征。与喂养标准配方奶粉的婴儿相比，接受膳食补充剂喂养的婴幼儿在出生的第一个月表现出更快的运动成熟和更强的视觉定向能力，更接近于通常在母亲喂养的婴儿中看到的模式。一项后续研究检测了这些猴子3岁时的心率变异性。尽管两组猴子在断奶后都一直在补充饮食，但服用配方奶粉的猴子表现出的心率变异性比在婴儿时期服用标准配方奶粉的猴子要大得多。

This project investigates primate biobehavioral development through comparative longitudinal studies of rhesus macaques and other monkey species, with special emphasis on characterizing individual patterns of differential behavioral and physiological responses to environmental novelty and challenge and on determining long-term developmental consequences for individuals of different genetic backgrounds reared in different physical and social environments. Several studies completed this year focused on possible interactions between a polymorphism in 5-HTT, a candidate gene for impaired serotonergic function, and differential early social experience. We published the first report of a specific gene-environment interaction in a nonhuman primate species: rhesus monkeys with the "short" (LS) allele exhibited deficits in central serotonin metabolism relative to those with the "long" (LL) allele, but only if they had been nursery-reared; in contrast, LS monkeys reared by their biological mother had normal serotonin metabolism, suggesting a "buffering" effect of maternal rearing. We reported a similar buffering effect of maternal rearing for measures of state control and visual orienting obtained during infancy. Rhesus monkeys are notoriously aggressive as a species, relative to other macaques (indeed, relative to most other primates); by contrast, Barbary macaques are unusual in their relatively low levels of aggression. This past year we were able to genotype members of a group of free-ranging Barbary macaques with respect to the 5-HTT gene and, unlike the case for rhesus monkeys, we found no individuals with either the LS or the LL allele. Instead, all of the Barbary macaques sampled had an "extra long" (XL) allele, a form found in less than 2% of the rhesus monkeys genotyped to date. This past year we also characterized a polymorphism in the MAO-A receptor gene, demonstrated functional differences among the different alleles, genotyped the LCE rhesus monkey colony with respect to this polymorphism, and began analyzing a variety of behavioral and physiological measures as a function of genetic status and early rearing history. Our initial analysis revealed a significant allele x rearing history interaction for aggressive behavior during the juvenile years: whereas as mother-reared monkeys with the "7" allele initiated more bouts of aggression than those with the "5" or "6" allele, the reverse was found for nursery-reared monkeys. We also completed a study investigating the relationship between serotonin metabolism and measures of impulsive and aggressive behavior in adult female rhesus monkeys living in free-ranging naturalistic social groups. Previous work had demonstrated that low cerebrospinal fluid (CSF) concentrations of 5-HIAA, the primary central serotonin metabolite, were associated with a relatively high incidence of risky, impulsive behavior and socially inappropriate, violent aggression (but not with low-level, socially appropriate dominance behavior) in free-ranging adult males and in both adult male and female rhesus monkeys reared in captivity. Our analyses revealed that low CSF 5-HIAA concentrations in these free-ranging females were also associated with excessive risky, impulsive behavior but not with violent aggression; instead a significant negative correlation was found between CSF 5-HIAA and socially appropriate dominance behavior. Finally, we published a study examining the biobehavioral consequences of adding a long-chain essential fatty acid supplement to the standard diet of nursery-reared rhesus monkey infants, which effectively raised their serum levels to those characteristic of infants raised (and nursed) by their biological mothers. Nursery-reared infants receiving dietary supplements exhibited accelerated motor maturation and enhanced visual orientation capabilities during their first month of life relative to infants fed the standard formula, more closely resembling the patterns normally seen in mother-reared infants. A follow-up study examined heart rate variability in these monkeys when they were 3 years of age. Monkeys who had received the formula supplement exhibited significantly greater heart rate variability than their counterparts who had received the standard formula during infancy, despite the fact that both groups had been maintained on a supplemented diet following weaning.