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Ecological flexibility, extended lifespans, and large brains have long intrigued evolutionary biologists, and comparative genomics offers an efficient and effective tool for generating new insights into the evolution of such traits. Studies of capuchin monkeys are particularly well situated to shed light on the selective pressures and genetic underpinnings of local adaptation to diverse habitats, longevity, and brain development. Distributed widely across Central and South America, they are inventive and extractive foragers, known for their sensorimotor intelligence. Capuchins have among the largest relative brain size of any monkey and a lifespan that exceeds 50 y, despite their small (3 to 5 kg) body size. We assemble and annotate a de novo reference genome for Cebus imitator. Through high-depth sequencing of DNA derived from blood, various tissues, and feces via fluorescence-activated cell sorting (fecal-FACS) to isolate monkey epithelial cells, we compared genomes of capuchin populations from tropical dry forests and lowland rainforests and identified population divergence in genes involved in water balance, kidney function, and metabolism. Through a comparative genomics approach spanning a wide diversity of mammals, we identified genes under positive selection associated with longevity and brain development. Additionally, we provide a technological advancement in the use of noninvasive genomics for studies of free-ranging mammals. Our intra- and interspecific comparative study of capuchin genomics provides insights into processes underlying local adaptation to diverse and physiologically challenging environments, as well as the molecular basis of brain evolution and longevity. [ABSTRACT FROM AUTHOR]

Small human body size, or the ‘pygmy’ phenotype, is characteristic of certain African, Southeast Asian and South American populations. The convergent evolution of this phenotype, and its strong association with tropical rainforests, have motivated adaptive hypotheses that stress the advantages of small size for coping with food limitation, warm, humid conditions and dense forest undergrowth. Most recently, a life-history model has been used to suggest that the human pygmy phenotype is a consequence of early growth cessation that evolved to facilitate early reproductive onset amid conditions of high adult mortality. As we discuss here, these adaptive scenarios are not mutually exclusive and should be evaluated in consort. Findings from this area of research are expected to inform interpretations of diversity in the hominin fossil record, including the purported small-bodied species Homo floresiensis. [Copyright &y& Elsevier]