This study analyzed genetic variation in the ANNAT1 gene in populations of Arabidopsis lyrata from different soil types. Sequences were compared from individuals in two serpentine, one granitic, and one sandy population. Nucleotide diversity was higher across populations than within serpentine populations. Polymorphisms were found, including an amino acid change only present in serpentine populations, suggesting natural selection or genetic drift. The study aims to better understand genetic adaptation to serpentine soil.