We characterized the role of the DNA methyltransferase DNMT3A in the fate decisions of murine megakaryocyte-biased HSCs and in the differentiation of megakaryocytes and platelets. In this experiment, we isolated washed platelets from 4 WT and 4 Dnmt3a+/– germline mice (2 males and 2 females per group) and subjected them to proteomic analysis by mass-spectrometry. We sought to identify changes at the protein level that occur in platelets due to aberrant DNA methylation during the differentiation of upstream hematopoietic cells.