Submitted to: Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/22/2001
Publication Date: 4/3/2002
Citation: ANANIEV, E.V., VALES, M.I., PHILLIPS, R.L., RINES, H.W. ISOLATION OF A AND C GENOME-SPECIFIC DISPERSED AND CLUSTERED REPETITIVE DNA SEQUENCES FROM AVENA SATIVA. GENOME. 2002. V. 45. P. 431-441. Interpretive Summary: An understanding of the organization, function, and relationships of stretches of DNA that make up the genetic material of plant species is vital to modern efforts to genetically improve crop plants to make them more productive and nutritious. The genome, or total genetic material, of the cereal oat, like that in wheat and over half of all higher plant species, is a complex combination of the genomes of two or more ancestral species. The genomes of most higher organisms contain dispersed regions of DNA with no known function. These DNA sequences evolved in multiple copies to produce species-specific repetitive DNA. These repetitive DNA sequences can serve as fingerprints to trace the ancestral origin and relationships within the complex genomes of current species. We isolated sequences of repetitive DNA that could be traced to different ancestral oat species. In so doing we developed a procedure for efficient isolation of species- specific repetitive DNA sequences. This new procedure should also be applicable to other complex plant species. Both the specific repetitive sequences we isolated from oat and the generic procedure we developed are powerful tools plant geneticists will use to learn more about complex plant genomes for crop improvement.
Technical Abstract: DNA gel-blot and in situ hybridization with genome-specific repeated sequences have proven to be valuable tools in analyzing genome structure and relationships in species with complex allopolyploid genomes like hexaploid oat (Avena sativa L., 2n= 6x= 42; ACD genome). In this report we describe a systematic approach for isolating genome-, chromosome-, and region-specific repeated and low-copy DNA sequences from oat, but presumably applicable to any complex genome species. Genome-specific DNA sequences were first identified in a random set of A. sativa genomic DNA cosmid clones by gel-blot hybridization using labeled genomic DNA from different Avena species. A or C genome-specific DNA subfragments were used as screening probes to identify additional genome-specific cosmid clones in the A. sativa genomic library. We identified clustered and dispersed repetitive DNA elements for the A and C genomes that could be used as cytogenetic markers for discrimination of the various oat chromosomes. Som analyzed cosmids appeared to be composed entirely of genome-specific elements while others represented regions with genome-specific and non- specific repeated sequences with interspersed low-copy DNA sequences. Thus, genome-specific hybridization analysis of restriction digests of random and selected A. sativa cosmids also provides insights into the sequence organization of the oat genome.