It is an object to provide a novel diacylglycerol acyltransferase. The present invention relates to a diacylglycerol acyltransferase, a polynucleotide encoding the same, and so on. The present invention provides a polynucleotide comprising the nucleotide sequence of, e.g., SEQ ID NO: 1 or 4, a polynucleotide encoding a protein consisting of the amino acid sequence of SEQ ID NO: 2, an expression vector and transformant comprising the polynucleotide, a method for producing a lipid or fatty acid composition using the transformant, or a food, etc. comprising the lipid or fatty acid produced by the method.