1. human parasite evolution and human evolutionary medicine
Human biological and cultural adaptations have impacted the evolution of many non-human species sharing our ecosystems, including our parasites. Because many of our parasites flourish only under very specific human behaviors and habitats, are wholly dependent on us, and have evolved with us for thousands or millions of years, we can study when and how we first acquired these parasites, under which environmental and cultural conditions we are the most susceptible, and how these species have evolved and adapted to us and we in response to them to develop new insights into human evolutionary history, beyond (yet complementing) what can be learned from human genome data alone or from the fossil and archaeological records. Moreover, effects of human biology or behavior and/or parasite adaptations to this niche can affect vector competency status for parasite-transmitted diseases. We are using experimental, functional, and evolutionary genomics approaches to study these processes with initial projects on tapeworms, bedbugs, and lice.
We are also interested in how human behavior can affect non-human evolutionary biology at broader ecosystem scales. For example, how human selective hunting pressures may have led to evolutionary changes in the body sizes of terrestrial and marine animals. We have current projects in this area of research with lemurs (Madagascar), lizards (southeast USA), conch (Panama), and coyotes (western USA).
The initial stages of this research are funded by a grant from the Wenner-Gren Foundation.
2. human body size evolution
Modern humans and earlier hominins exhibit considerable body size variation – among individuals, between sexes, and across populations, and over time. At least within modern human populations, a large proportion of this variation is explained by genetic factors, and we currently have as much or more information on the underlying genetic architecture of body size variation as we do for any complex, polygenic human trait. Our lab is using this information, alongside ancient DNA and morphological data and results from our own experimental work, to study the evolutionary history of human body size variation.
We have current projects in this area on the evolution of human body size sexual dimorphism, on the effects of childhood health and nutrition on adult stature (accounting for genetic effects with ancient DNA data) across the Neolithic agricultural transition, and on the convergent evolution of the small body size ‘pygmy’ phenotype among worldwide rainforest hunter-gatherers. Here, one of our approaches is to identify convergent signatures of natural selection in the genomes of both African and Southeast Asian rainforest hunter-gatherers. We are also performing experiments with cryopreserved cell lines (including induced pluripotent stem cells, iPSCs) to study genome-wide growth hormone gene regulatory response differences between hunter-gatherers and neighboring agriculturalists.
This research is funded by grants from the National Institutes of Health and the Wenner-Gren Foundation and by Dr. Perry's Harry J. and Elissa M. Sichi Early Career Professorship.
3. primate genomics and paleogenomics
We are also passionate about non-human primate evolutionary ecology and conservation biology. While much of our past work in this area has focused on lemurs, the primates of Madagascar, we have also studied or are currently performing genomic-scale studies with tarsiers, old world monkeys, new world monkeys, and apes! In addition, we are studying how long histories of human-environment interaction relate to present-day primate conservation issues. Most specifically, we are using high-resolution population genomic methods to reconstruct demographic histories of the Malagasy people, their introduced cattle, and various lemurs, to then compare these results to each other and to paleoclimate data.
We are also using genomic data to test hypotheses about longer-timescale non-human primate evolutionary ecology. On Madagascar, the 100 or so extant lemur species are widely known for their incredible diversity (and we have conducted evolutionary genomic studies of multiple of these taxa). Yet, only several thousand years ago, lemur diversity was considerably greater: From skeletal remains, we know of at least 17 now-extinct species that lived as recently as 500 years ago. These “subfossil” (the bones are unmineralized) lemurs were each larger than any extant lemur, some substantially so -- up to the size of a male gorilla! We are analyzing paleogenomic data from our ancient DNA laboratory to study the behavioral ecology (e.g. diet adaptations and taste and visual perception) of the extinct, giant subfossil lemurs.
These projects are currently funded by grants from the National Science Foundation.