DNA Sequence Diversity in Alcohol Dehydrogenase Genes from Pines

Molecular clones that represent ADH coding sequences (cDNA clones) from Monterey pine have been been isolated and characterized. These clones have been subsequently used to identify DNA fragments containing homologous sequences in samples of DNA prepared from needles of mature loblolly and Monterey pine trees. Relative to analogous studies of ADH from angiosperms, the number of fragments in pines is large. Just how these homologous sequences are related to each other is currently under investigation. Genomic libraries have been constructed in a bacteriophage vector (EMBL3) for both loblolly and Monterey pines. Several million recombinant phage were screened using our ADH cDNA clones as molecular probes. We identified a large number of clones containing sequences homologous to our probes, a result that is consistent with our studies of restriction fragments. Preliminary analyses of DNA purified from these clones suggest that many contain DNA sequences from different portions of the genuine. In combination, these data suggest that ADH in pines may belong to a gene family that contains more members than suggested from studies of isozymes (i.e. 2-4 loci). Alternatively, pine ADH genes may themselves be very large, containing many or large intervening (non-coding) sequences in addition to a normal complement of coding sequences.

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Author(s): D. E. Harry, K. S. Mordecai, C. S. Kinlaw, Carol A. Loopstra, Ronald R. Sederoff

Publication: Tree Improvement and Genetics - Southern Forest Tree Improvement Conference - 1989

Section: General Session: Biotechnology