We want to understand how human bodies are built. Which genes determine our unique human characteristics? How do these genes differ in people who look, feel or behave in different ways? Can we reveal patterns that explain why some of our genetic differences cause us problems while others simply make us unique?

The popularity of personal genetic sequencing together with digital tools to engage broad audiences provide an exciting opportunity to make new discoveries about how human bodies are built. Scientists from the Tabin Lab at Harvard Medical School are seizing this unprecedented technological moment to ask fundamental questions about how our genomes build our unique human bodies.

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Circles in Human Evolution is a scientific research study that is diving into the biology of one interesting and understudied human trait: the areola. The areola is a circle of specialized, pigmented skin surrounding the human nipple. Areolas are a mysterious but universal human marking. They have been proposed to play an intriguing role in human evolution; differences in areola morphology have been linked to sexual selection, nursing behavior, and infant weight gain. Developmentally, circular markings have a simple genetic architecture, making the areola both an interesting and a practical case study into the genetic architecture of distinctively human traits.

The Circles in Human Evolution project aims to investigate diversity in the human areola. Our goals are to 1) characterize all externally visible aspects of the areola and 2) discover the genes responsible for variation in the appearance and glandular structure of the areola. We are recruiting adult participants who have undergone personal genetic sequencing to share their areolar characteristics and genetic data with us through  an online survey. Using self-reported observations, measurements, and optional photographs, we hope to understand fundamental aspects of how areolas are built, how they evolved, and how their diversity might effect everything from breast health to nursing.

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Interested in joining our study? If you are an adult who has personal genomic sequence to share, we would love to have your help with our study. To read more or join, use this link to check out our study page at Open Humans:

Click here to log in and join Circles


Please email any questions or comments to Abigail Wark, Project Director: