Research

Our lab explores the variation in human appearance, focusing on hair and skin. We aim to unravel the distribution of this variation across populations, its genetic underpinnings, as well as its evolutionary history. Our interest extends from theoretical considerations to practical, quantitative analyses of the metrics and classification systems used to describe human variation. Ultimately, this lab seeks to contribute to our collective knowledge of human evolutionary biology and to improve innovations in biomedicine and technology by better accounting for human variation.

Quantitative phenotyping

  • The methods we use shape our understanding of traits and can improve or hinder our ability to see certain kinds of variation. We are a methods-agnostic lab—our goal is to figure out the best approach to understanding variation in our phenotype of interest. We employ a range of methods to generate and analyze our data, from those we develop and perform in-house to those we work with collaborators to apply to our data.

    Traits we’re interested in measuring include: pigmentation (skin, hair, eyes), hair morphology, facial morphology. Methods we’ve used before and are interested in: image analysis/computer vision, broad spectrum reflectance spectrophotometry, high-performance liquid chromatography.

    We believe that studying the best way to measure traits can impact our ability to answer theoretical biological questions about them as well as medical, forensic, and technological applications that rely on the ability to measure those traits accurately.

  • Developing lab protocols

    We’ve developed new ways of preparing hair samples for measuring their curvature and published those protocols.

  • Innovating with simple tools

    We’ve developed ways of embedding hair samples for cross-sectional microscopy with polycaprolactone, more commonly known as moldable plastic.

  • Imaging & microscopy

    We use a range of different imaging methods and microscopy tools to get at various aspects of hair shape and color.

  • Measuring skin color

    We’re interested in measuring skin color and understanding how various tools for capturing differences in skin color compare.

Evolutionary biology

  • Why does hair curl? Why do some people have deeply pigmented skin? Why does puberty signal the growth of hair in certain regions of the body? Such questions can be answered on multiple levels. We can ask what the genetic basis is of such traits and what happens throughout the course of an individual’s life to create that trait or change that trait. We can also ask on the level of populations and even species whether natural selection has played a role in shaping what that trait looks like in some groups compared to others.

    We investigate the hormonal, genetic, and epigenetic mechanisms that contribute to variation in hair morphology and skin pigmentation and measure variation in these traits. By examining mechanisms and the distribution of variation, we aim to gain insights into the evolutionary forces that have shaped these traits over time, and how they have contributed to the diversity of human appearance that we observe today.

  • Investigating evolutionary hypotheses

    We want to find evolutionary explanations for the (distribution of) human trait variation that we see in the world

  • Genetic architecture of traits

    The quantitative phenotyping we do is used in conjunction with genetic data to better understand the relationship between phenotype and genotype.

  • Phylogenetic patterns

    Our desire to understand the evolution of hair and pigmentation extends beyond humans to non-human primates and other mammals. We are interested in evolutionary analyses that look at patterns across taxa.

Biotech applications

  • Pulse oximeters, now famously, are an example of a case when a tool’s performance is affected by skin color, due to the reliance on light absorption and variation in light absorption between people. However, it is not enough to note this discrepancy, we have to combine quantitative knowledge of variation in skin reflectance with an understanding of methods that can detect bloodflow through the skin.

    We are exploring the relationship between hair and skin variation and biomarkers that can inform fertility and overall health. We are investigating non-invasive ways of measuring hormones and other biomarkers through hair and, particularly, understanding how variation in hair morphology affects values measured. In skin, we are studying how variation in the quantity and distribution of melanin, as well as structural variation in the skin, can affect diagnostics based on skin optics.

    Other technological applications that we are invested in researching for the purpose of equitable performance include facial recognition and computer graphics/biophysical simulations of hair and skin.

  • Calibrating with objectively measured skin color

    From dermatology to computer graphics, various fields require an understanding of human skin color variation. Yet, many rely on crude categories. We’re interested in providing data in an understandable way that could help people in various fields calibrate tools to the full breadth of human skin color variation.

  • Hair variation and biomarkers

    Hair contains various biomarkers that are used to understand human health (incl toxicology). But variation in hair thickness and texture is not accounted for and can complicate our ability to interpret values across individuals.

  • Facial recognition

    We are keen on guiding the development of equitable machine learning training datasets. Without adequately trained facial recognition datasets, widely-used software may underperform for certain groups. However, delineating the right proportions of individuals with a diverse range of traits is challenging, and this is an area we are interested in exploring.

Societal impact

  • We like to ask big questions. How do concepts of race affect our society? Ideas about classification and race permeate into forensics and therefore the justice system—what consequences does that bring? Advances in technology and the accumulation of large databanks bring with them biases in who is sampled and questions of consent.

    Within this realm, we also include our science communication work. Whether it is for the public, or for scientists in other disciplines, or medical professionals, we believe that providing better tools and frameworks for understanding human variation can improve our society.

  • Impact on the justice system

    The speed of technological advancement far outpaces the speed of policies and laws adapting. We’re interested in understanding biases and other unforeseen issues with forensic technologies.

  • Ethics and inclusivity

    It is widely accepted that not all populations benefit equally from advancements in genomics. But how can we include marginalized populations in research while fostering trust and ensuring active, informed participation?

  • Categorizing color and human taxonomies

    Various scales and classification systems are used to divide humans into categories: whether as a whole or by particular traits. We are interested in critically examining what those categories are and whether they are biologically informed and what the consequence is of using them for e.g. dermatological diagnoses.