Research

An Integrative Approach

Our lab explores how genes influence skeletal variation and how this has evolved through time. Over the years, lab members have used quantitative genetic approaches, studied gene expression in early development, and assessed in utero effects on bone development. All the while, we conducted paleontological field research in Tanzania, Kenya, and Ethiopia to collect evidence for how skeletal morphology has evolved over geological time.

Due to resource constraints and budget cut-backs on campus, we no longer conduct wet lab research, although we had exciting results from our studies of gene expression in marsupial tooth development (Moustakas et al. 2011 Developmental Dynamics 240(1):232-9), endentulousness in turtles (Lainoff et al. 2015 Molecular and Developmental Evolution (J. Exp. Zoolog.) 324(3):255-69), and are wrapping up work on frog tooth development (Grieco & Hlusko, in press, Anatomical Record).

These days, and for the foreseeable future, we are focusing our efforts on paleontology and developing approaches for exploring large phenotypic datasets to discern the underlying genetic architecture.

Field Paleontology: Olduvai Gorge

Our primary field project is the the Olduvai Vertebrate Paleontology Project, and its complement the Comprehensive Olduvai Database Initiative. Please visit the project website at www.olduvai-paleo.org for information on these National Science Foundation supported endeavors.

Photo credit: Whitney Reiner, 2008
Photo credit: Whitney Reiner, 2008

Field Paleontology: The Tanzania Survey Project

The Olduvai project started as an off-shoot of the Tanzanian International Paleoanthropological Research Project. TIPRP is co-directed by Drs. Hlusko and Jackson Njau from Indiana University. Tanzania remains relatively unexplored in terms of human evolutionary research. All of the known sites that have yielded remains of our ancestors are located in the north, such as Olduvai Gorge and Laetoli. We studied recently released NASA satellite imagery (thank you Google Earth for help with a lot of this work) and geological maps, and from these found potentially fossiliferous sediments in areas that have not yet been explored for their paleoanthropological potential. Our goal is to inventory and document previously unknown localities. Results from our first few years of fieldwork have been published in the Journal of Human Evolution (2010, vol 59:680-684) and Geochimica et Cosmochimica Acta (2012, vol 93:129-142)

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TIPRP field crew, 2008. Photo credit: L. Hlusko

Large Scale Studies of Skeletal Variation

In collaboration with Dr. Michael Mahaney at the University of Texas Rio Grande Valley School of Medicine and other scientists at the Southwest National Primate Research Center, Dr. Hlusko has been undertaking a quantitative genetic analysis of dental variation in baboons. This work, published primarily between 2001 and 2011, provided the foundation for our research exploring the genetic architecture across primates, for example, see our cover article in Evolution (Jan 2013) and others published more recently.

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The baboon quantitative genetics research spun off into a quantitative genetic analysis of dental variation in wild type mice, finding a conserved pattern of genetic modularity (Molecular and Developmental Evolution, 2011, vol 316B:21-49). We hypothesize that this genetic modularity underlies mammalian dental variation more broadly. We are currently working on a project quantifying dental variation across numerous mammalian groups to test this.