Last night PhD candidate @TinaLasisi of Penn State University gave the latest CSHO colloquium webinar on her research regarding "genomes, phenomes and scientific narratives of racialized traits." We’ll provide a brief summary of what we learned in this thread: (1/12)

. @TinaLasisi studies genetic and phenotypic variation in skin pigmentation and hair morphology. (2/12)

Her work emphasizes the importance of carefully considering how we talk about phenotypes, particularly for racialized traits like skin and hair (i.e. are the terms we use biologically informed or are they subjective labels?) (3/12)

Hair types are often classified using a 3-point categorical system (straight, wavy, curly), but @TinaLasisi’s work shows that this system is far too subjective, and oversimplifies the incredible variation found in hair types across the globe (4/12)

Is it better to quantify aspects of hair morphology rather than categorize hair types? Absolutely! (5/12)

Using measures like hair curvature and the relative ellipticity of hair cross-sections, @TinaLasisi finds that hair morphology is complex and there are likely many factors that determine overall hair ‘texture’ (6/12)

The way we categorize hair colors (e.g. red, blonde, light-brown, dark brown/black) is also flawed. (7/12)

Tina’s work finds that there is much more variation in melanin content on the darker hair color spectrum than the lighter spectrum. There is more variation in melanin in the darkest hair colors than in blonde and light-brown hair combined! (8/12)

So what are some big takeaways? We need to find biologically meaningful phenotypes, rather than relying on simple classification schemes, particularly when we talk about racialized traits. Thoughtful phenotyping will lead to better science (9/12)

Another big takeaway? Racialized traits like skin pigmentation and hair morphology/color are subject to Eurocentric classification schemes. (10/12)

We miss out on an incredible amount of variation if we assume that hair color and morphology is only diverse in people of European ancestry, rather than assessing these traits quantitatively (11/12)

Lastly, a huge thanks to @TinaLasisi for giving the latest CSHO colloquium webinar and sharing her work on genetic and phenotypic variation in skin pigmentation and hair morphology (12/12)