MAIZE SIMPLE REPETITIVE DNA-SEQUENCES - ABUNDANCE AND ALLELE VARIATION

Microsatellites or simple sequence repeats, first demonstrated in huma n and other mammalian genomes, are being identified in many plant spec ies. A database survey of 576 maize sequences from the GenBank and EMB L databases was made to determine the abundance of maize microsatellit es. Two hundred potential microsatellites were identified. The relativ e abundance of the different repetitive motifs varied considerably and all possible dinucleotide and trinucleotide motif types were found. T he three most abundant classes of microsatellites identified in this s earch were (AG/CT)(n), (CCT/GGA)(n), and (CCG/GGC)(n) repeats. Allelic variation was surveyed with 9 maize inbred lines representing diverse pedigrees. Amplification of DNA from these lines and analysis using h igh resolution agarose gels showed that 69 of the 200 potential micros atellites were polymorphic and yielded 2-4 alleles. A more complete sc reen of these loci against a wider array of maize germplasm using dena turing sequencing gels is now being conducted to more thoroughly evalu ate these loci.