This project focuses on Caenorhabditis elegans. Quantitative mass spectrometry (MS) was performed on histone H3 extracted from whole-worm samples to characterize histone H3 methylation. Wild-type and set-19 mutant backgrounds were analyzed and modification patterns were compared between the two genetic backgrounds. Raw mass spectrometry data were processed and quantitatively analyzed using EpiProfile 2.1_Celegans.