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Abstract
Apospory is a form of gametophytic apomixis in which embryos develop from unreduced embryo sacs derived from nucellar cells of the ovule bypassing meiosis and fertilization of gametes. Apospory in the Pennisetum and Cenchrus species is controlled by a physically large, hemizygous, heterochromatic chromosomal block called the apospory-specific genomic region (ASGR). Two major studies were conducted to identify possible synteny of the ASGR-carrier chromosome in Pennisetum squamulatum to related and sequenced reference genomes and to use Illumina duplex specific nuclease (DSN) generated sequences to produce additional genetic markers for the ASGR. In the first study, macro-collinearity of the ASGR-carrier chromosome in P. squamulatum, outside the ASGR , to chromosome 2 of sorghum and foxtail millet was identified based on physical mapping of eight bacterial artificial chromosome (BAC) clones carrying ASGR-carrier chromosome markers as compared to the location of the orthologous gene on chromosome 2 of sorghum and foxtail millet. In our second study, we were able to genetically map more than 85% of sequence characterized amplified region (SCAR) markers developed from duplex specific nuclease normalized Illumina sequences, to the ASGR in P. squamulatum.