Characterization of a recombinant inbred line population for quantitative trait locus mapping

Abstract only availableEukaryotes can regulate gene expression by epigenetic mechanisms at the chromatin level. One epigenetically regulated gene in maize is Pl1-Blotched, an allele of purple plant1, which activates anthocyanin pigment production. Normally, Pl1-Blotched leads to a variegated pattern of pigmentation, but its pigment level can be increased by a modifier called Suppressor of plant blotching (Spb). At the molecular level, Spb alters the chromatin packing of Pl1-Blotched, leading to less tightly packed chromatin and higher gene expression. The genetic identity of Spb is not yet known, although preliminary results indicate the Spb-enhanced pigment phenotype is a quantitative trait. As a step toward isolating the genes for Spb, a mapping population of Recombinant Inbred Lines (RILs) was generated by inbreeding the progeny of an F2 derived from a cross of Pl1-Blotched with Spb to a less pigmented Pl1-Blotched stock. Genotypes were determined for 188 RILs using microsatellite or simple sequence repeat (SSR) markers. RILs were evaluated for residual heterozygosity, breakpoint locations, and heterozygous chromosomal positions. A map was created and will be used as the foundation for mapping Spb and for estimating the heritability of the Spb phenotype.NSF-REU Program in Biological Sciences & Biochemistr