Tracing the Phylogeny of the Hexaploid Oat Avena sativa with Satellite DNAs

The genus Avena contains 30 different species from diploid through tetraploid to hexaploid with different genome compositions. Research regarding the origin of the different genomes in the polyploid species has been inconclusive. The objectives of this research were to investigate the phylogenetic relationships of the Avena species by means of polymorphisms in satellite, minisatellite, and microsatellite DNA. A satellite DNA sequence, ASS49, was isolated from a microsatellite‐enriched library of the hexaploid oat Avena sativa L. Southern hybridization showed that ASS49 was a species‐specific rather than a genome‐specific satellite. ASS49 was able to distinguish species that may be the diploid and tetraploid progenitors of hexaploid oat. The phylogenetic relationship of Avena species was further investigated using 40 microsatellite and four minisatellite primers. These results appeared to support the findings with ASS49. It appears that the Ac‐genome diploid species (A. canariensis Baum Raj. et Samp.) is the progenitor and A‐genome donor of the hexaploid oat rather than the generally believed As‐genome species (A. strigosa Schreber). Instead, A. strigosa appears to be a member of a separate lineage of diploid and tetraploid species including the tetraploid species A. abyssinica Hochst.