A copy of exon 3-intron 3 from the barley aleurain gene is present on chromosome 2.

A genomic clone from Hordeum vulgare L. cv. Himalaya contains 700 bp of DNA that is homologous with a high degree of nucleotide sequence similarity to exon 3-intron 3 from the gene for the thiol protease, aleurain. Genomic Southern blot mapping data indicate that this clone in phage lambda had not undergone rearrangement, and no other sequences homologous to aleurain are present on it. Although exon 3 in aleurain encodes the polypeptide region cleaved during proteolytic processing of the proenzyme to its mature form, we do not know if the copy is expressed in some other protein. We have mapped the aleurain gene to chromosome 1, and this copy of exon 3-intron 3 to chromosome 2.