One over PAR or one under PAR: Vive la difference

The concept of race based on physical appearance, social grouping, or selfidentification has been challenged for decades. With the recent sequencing of thousands of human genomes, this concept has been further redefined. In this issue of Blood, Heenkenda et al show that the A allele frequency of the F2RL3 rs773902 A/G dimorphism associated with increased platelet reactivity is significantly lower in Somalians than what has been previously described for blacks in the United States, underscoring the importance of genetics and geographic ancestry for determining disease risk.