Simple sequence repeat markers developed from maize sequences found in the GENBANK database: Map construction

Simple sequence repeats (SSRs) are rapidly becoming an important class of DNA markers that are being widely used to map both pi ant and animal genomes. SSRs have the advantage of providing a codominant marker system based on polymerase chain reaction (PCR) methodology. Although the presence of SSRs is now wed documented in the plant kingdom, a mapped set of primer sequences in maize (Zea mays L.) is not available. Polymorphic primer pairs developed from maize sequences in GENBANK were mapped to 42 loci in maize by means of either a B73 x Mo17, Mo17 x H99, or B73 x G35 recombinant inbred population. All SSR loci were found to be linked to one or more adjacent restriction fragment length polymorphism (RFLP) and/or isozyme loci. Segregation followed a pattern of Mendelian inheritance with one SSR locus deviating from expected ratios at a 1% level of significance. The SSRs were distributed throughout the maize genome with no evidence of clustering. Each SSR marker detected a single locus.