Plant & Animal Genomes XVI Conference Plant & Animal Genomes XVI ConferenceJanuary 12-16, 2008
Town & Country Convention Center
San Diego, CA
We are studying naturally-occurring quantitative variation in male and female gametogenesis in wild populations of the apomictic Boechera (formerly Arabis) holboellii complex. Our ongoing work in Boechera has demonstrated high levels of genomic variation, including polyploidy, aneuploidy, extensive genomic microduplications, and meiotic variation ranging from fully synaptic, to partially-synaptic, to completely asynaptic accessions. We have documented similar levels of variation in pollen and seed formation in Boechera which, importantly, has enabled us to differentiate between phenomena which are directly and secondarily associated with apomixis. We have used these data to select 2 sexual and 2 highly-expressive apomictic accessions for ovule microdissections, from which we have recently sequenced over 450 000 mRNA tags in a SUPERSAGE analysis. This transcriptomic analysis has identified over 4000 mRNA tags which are either (1) only expressed in sexual or apomictic ovules, or (2) significantly differentially expressed when comparing sexual and apomictic ovules. We have complemented these data using 454 technology to sequence the complete transcriptomes of sexual and apomictic ovules such that full-length gene sequences can be obtained for each candidate. The expression patterns of these candidate mRNAs are presently being screened in different microdissected tissues taken from a large number of genotypes in order to confirm their expression specificity for either reproductive mode on the population level.