Plant & Animal Genome VI Conference

P13

THE CHICKEN ALPHA-AMYLASE LOCUS: STRUCTURAL ORGANIZATION AND CHROMOSOMAL LOCALIZATION.

1. Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta, Canada, T1J 4B1
2. Agriculture and Agri-Food Canada, Centre for Food and Animal Research, Ottawa, Ontario, Canada, K1A 0C6.
3. Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, Ontario, K1N 6N5.
4. Department of Animal Science, University of Minnesota, St. Paul, MN, U.S.A., 55108-6010.

We have determined the chromosomal location of the chicken amylase locus by flourescent in situ hybridization (FISH) to metaphase spreads from chicken embryos. In addition, we have sequenced over 11 kbp of genomic DNA spanning the chicken amylase region. Sequence analysis revealed the presence of a functional amylase gene and a pseudogene in a head-to-head configuration, separated by an intergenic region of about 2 kbp. The expressed gene copy spans over 4 kbp, contains nine introns and encodes a preprotein of 512 amino acids. The protein-coding portion of the expressed genomic copy is identical in sequence to a cDNA derived from chicken pancreas by RT-PCR; the pancreas is the main site of amylase production in the chicken. In comparison to the expressed gene, the amylase pseudogene is internally deleted and truncated. We have also isolated an amylase cDNA clone from a chicken liver library. This clone is different in nucleotide sequence from the pancreatic cDNA. We are currently completing the characterization of the liver cDNA clone and are searching for its genomic equivalent. Thus, our current evidence indicates that the amylase gene family in chickens is small, consisting of 2 expressed loci (one pancreas- and one liver-specific) plus a single pseudogene located 2 kbp from pancreatic gene copy.