W568 Tales of a successful hybrid: retracing the steps of the natural allopolyploid A suecica

Date: Saturday, January 14, 2012
Time: 5:10 PM
Room: Golden West
Isabelle Henry , UC Davis, Davis, CA
Brian P. Dilkes , Purdue University, West Lafayette, IN
Anand Tyagi , University of the South Pacific
Jennifer Monson-Miller , UC Davis, Davis, CA
Brian Christensen , University of Washington
Brian Waston , UC Davis, Davis, CA
Luca Comai , UC Davis, Davis, CA
Newly formed hybrids are faced with multiple challenges in order to produce a viable lineage.  In plants, the immediate problem of meiotic chromosome pairing is often alleviated by a whole-genome duplication event, producing an allopolyploid. Within the Arabidopsis genus, crosses between the well-known model A. thaliana and its close relative A. arenosa can produce such allopolyploid hybrids, which can be robust but exhibit low fertility. The natural allopolyploid A. suecica originated from a single hybridization event between A. thaliana and A. arenosa, approximately five thousand years ago. These two allopolyploids, the natural A. suecica and the synthetic thus provide a unique system to investigate the mechanisms involved in adaptation to allopolyploidy. Through a combination of whole-genome sequencing and transcriptome analysis, we report on the genomic structure and the pattern of gene duplication of A. suecica.  An F2 population was created, originating from a cross between the synthetic and the natural allopolyploid, segregating for all four parental genomes. Each progeny was characterized in details for growth and fertility-related phenotypes, as well as for meiotic irregularities (via FISH). Genotype information was obtained through next-generation sequencing for QTL mapping. Some but not all individuals with low pollen viability exhibited meiotic abnormalities, suggesting that other mechanisms might be at play. Overall, 15 percent of the F2 progeny were aneuploid. Results of the QTL mapping will be discussed.