Plant & Animal Genomes XI Conference

January 11-15, 2003
Town & Country Convention Center
San Diego, CA

Workshop: Apomixis
            

GENETIC DISSECTION OF AUTONOMOUS APOMIXIS IN TARAXACUM

Netherlands Institute of Ecology, PO Box 40, 6666 ZG, HETEREN, The Netherlands

Segregation ratios of apomixis in crosses between sexual and apomictic dandelions (Taraxacum officinale) suggest that apomixis is controlled by several independent dominant genetic factors. Two microsatellite markers have been found that are closely linked to diplospory (avoidance of meiosis). A third microsatellite marker is closely linked to parthenogenesis. The chromosomal segments marked by these microsatellites show strong segregation distortion with respect to haploid and diploid pollen grains. In a fine-mapping project 25 AFLP markers have been identified that are closely linked to diplospory. These markers are evenly distributed around the diplospory locus and so far we have no indication for suppression of recombination, nor for hemizygosity in this chromosomal region. At the moment the closely linked AFLP markers are converted into SCARs for comparative mapping, chromosomal FISH and the screening of large mapping populations.