Genetic Origin of Variation in Human Skin Color

This activity guides the analysis of a published scientific figure from a study that investigated a gene involved in determining human skin color.

This study focused on the gene SLC24A5, which codes for a protein involved in melanin production. Variations in this gene are associated with variations in human skin pigmentation. The scientists considered two alleles of SLC24A5: an ancestral allele “G” and a derived allele “A.” The figure shows the different distributions in human skin pigmentation (melanin index) for three SLC24A5 genotypes (GG, AG, and AA), relative to a regression line calculated for the GG genotype. The “Educator Materials” document includes a captioned figure, background information, graph interpretation, and discussion questions. The “Student Handout” includes a captioned figure and background information.