A DNA molecule (I), encoding a plant protein with fucosyl transferase activity, comprising a 2198 base pair sequence, fully defined in the specification, with an open reading frame of nucleotides 211-1740, a sequence at least 50 % homologous to it, a sequence hybridizing to it under stringent conditions, a sequence which differs due to genetic code degeneracy, or their complement, is new. Independent claims are also included for the following: (1) a DNA molecule (II), comprising a 105 base pair sequence, fully defined in the specification, a sequence at least 95 % homologous to it, a sequence that hybridizes to it under stringent conditions, or a sequence which differs due to genetic code degeneracy； (2) a DNA molecule which is a partial sequence of (I) or (II), which comprises 30-50 base pairs； (3) (I) or (II) covalently associated with a detectable marker substance； (4) a biologically functional vector comprising (I) or (II) or a partial sequence of at least 20 base pairs； (5) a biologically functional vector comprising (I), (II) or a partial sequence in inverse orientation to the promoter； (6) (I), (II) or the DNA molecule of (2) or (3) comprising a deletion, insertion and/or substitution mutation； (7) a DNA encoding a ribozyme, which comprises two sequence sections of at least 10-15 base pairs, which are complementary to (I) or (II), so that the ribozyme complexes with and cuts the mRNA, which is transcribed from a natural GlcNAc-alpha 1,3-fucosyl transferase DNA molecule； (8) a biologically functional vector comprising DNA of (6) or (7)； (9) producing a cDNA of (I) or (II) comprising isolating RNA of insects or plants, and carrying out reverse transcription with a reverse transcriptase and primers； (10) cloning a GlcNAc-alpha 1,3-fucosyl transferase； (11) producing recombinant host cells which over-express GlcNAc-alpha 1,3-fucosyltransferase； (12) producing recombinant host cells, preferably plant or insect cells, which have a DNA of (6) in place of the non-mut
