The present invention relates to diacylglycerol acyltransferase genes and proteins, and methods of their use. In particular, the invention describes genes and proteins that exhibit both long-chain acyltransferase and acetyltransferase activity. The present invention encompasses both native and recombinant wild-type forms of the transferase, as well as mutants and variant forms, some of which possess altered characteristics relative to the wild-type transferase. The present invention also relates to methods of using diacylglycerol acyltransferase genes and proteins, including in their expression in transgenic organisms and in the production of acetyl-glycerides in plant oils, and in particular seed oils.