Research at Cayo Santiago
Image credit: Raisa Hernández
Evolutionary genetics of non-reproductive sexual behavior, including homosexuality
Professor Vincent Savolainen, Imperial College London, UK
Homosexual behaviour is common in several animal species – including humans. This has often been considered a 'Darwinian paradox' as non-reproductive sex will result in fewer descendants and lead to extinction. Nevertheless, genetic factors seem to influence the likelihood that an individual will engage in sex with a same-sex partner. However, human genetic studies have often lacked statistical power and/or are limited by the confounding effects of cultural practices and the environment at large. Here, we turn instead to a unique resource, the free-ranging colony of rhesus macaques on Cayo Santiago Island. We propose the first ever study quantifying the evolutionary mechanisms and functions of same sex mating behaviour in nature. Using extensive behavioural data and cutting-edge genomic analyses, our results should lead to re-thinking of the prevalence and causation of same sex mating behaviour in wild primates, with relevance to human societies.
A longitudinal analysis on the variance of extra-group paternities in rhesus macaques
Angelina Ruiz-Lambides, M.A., PhD., Caribbean Primate Research Center, University of Puerto Rico
Alternative mating strategies, such as extra-group paternities (EGP), may be driven by the divergence of reproductive interests between males and females. EGPs may counteract negative fitness consequences, contribute to genetic variance or change group stability. They have broadly been described in several species of non-human primates, wherein genetic data of a few birth cohorts of a given social group revealed that a proportion of offspring are typically sired by males not resident to the social group at the time of offspring conception. Whereas much has been discussed about the occurrence of surreptitious matings, minimal work has been done to analyze factors leading to EGPs in non-human primates. My study will comprise nine years of demographic, dominance and genetic data of all groups of the rhesus macaque population of Cayo Santiago. We will investigate EGPs from different perspectives including from the social group level, male and female individual perspective.
Genomic consequences of the social environment and resilience during aging
Dr. Noah Snyder-Mackler, University of Washington
As in humans, the social environment has also been linked to mortality in some nonhuman primates, including close relatives of macaques. More socially integrated individuals are healthier and live longer than less integrated individuals, and this association is the strongest in the oldest individuals in a population. To identify the molecular underpinnings of this link, we draw behavioral and genomic data from Cayo Santiago rhesus macaques. We merge cutting-edge functional genomic analyses (RNA-seq, ATAC-seq, and novel single-cell approaches) with behavioral observation methods to study how behavioral variation might insulate individuals from the detrimental effects of social adversity on health
This research has implications for understanding how social adversity recapitulates, or even accelerates, the changes seen during normal aging. More broadly, identifying the molecular phenotypes on which natural selection acts will lead to a better understanding of both the evolution of affiliative social behaviors and the well-documented link between sociality and components of fitness.
The biological basis of social relationships and cooperation
Dr. Lauren Brent, University of Exeter
The aim of this research is to determine why social relationships are formed and how they are maintained. Within groups, individuals differ in their tendencies to interact with others and in how deeply embedded they are in their social networks. This research investigates the heritable basis of individual differences in sociality, along with their physiological causes and impacts on health, life-history, and fitness. In addition, this research ex