Abstract: .alpha.-Amylase, an enzyme that hydrolyses starch, can be found in all plants. The modification of potato starch production, in particular, is important in the preparation of various food products. The present invention discloses nucleotide sequences of potato .alpha.-amylase genes and the corresponding amino acid sequences. The present invention also describes DNA probes comprising .alpha.-amylase nucleotide sequences, as well as expression vectors that produce active .alpha.-amylase enzymes. These expression vectors can be used to produce transgenic potato plants.