Polyunsaturated fatty acid synthase nucleic acid molecules and polypeptides, compositions, and methods of making and uses thereof

A method of identifying a nucleic acid molecule comprising a polynucleotide sequence encoding a polypeptide comprising PUFA synthase activity of ER activity and DH activity, the method comprising:

• screening for a nucleic acid molecule from an organism that hybridizes to the complement of a polynucleotide sequence at least 95% identical to SEQ ID NO:5 or a polynucleotide sequence encoding a polypeptide which comprises an amino acid sequence at least 95% identical to SEQ ID NO:6, and determining the PUFA synthase activity of the nucleic acid molecule that hybridizes, wherein the nucleic acid molecule is capable of hybridizing under stringency conditions comprising post-hybridization washes selected from the group consisting of:
• (1) a series of washes starting with 6×SSC and 0.5% SDS at room temperature for 15 min., then repeated with 2×SSC and 0.5% SDS at 45° C. for 30 min., and then repeated twice with 0.2×SSC and 0.5% SDS at 50° C. for 30 min.;
• (2) a series of washes starting with 6×SSC and 0.5% SDS at room temperature for 15 min., then repeated with 2×SSC and 0.5% SDS at 45° C. for 30 min., and then repeated twice with 0.2×SSC and 0.5% SDS at 60° C. for 30 min.;
• and (3) a series of washes starting with 6×SSC and 0.5% SDS at room temperature for 15 min., then repeated with 2×SSC and 0.5% SDS at 45° C. for 30 min., and then repeated twice with 0.1×SSC and 0.1% SDS at 65° C.