玉米基因组的简单重复序列遗传研究进展

Advance in DNA Repeat Sequence of Maize Genome

Maize contains about 3X109base pairs of DNA per haploid genome,of which approximately 80% is repetitive,highly repetitive DNA sequence could be found within either 3 or 5 to the structure gene.These highly repetitive regions were each composed of unique combinations of different short repetitive sequence.5—methelation of cytosine in sequence 5—CG—3 and 5—CNG—3 were localized within or near highly repetitive DNA.Simple sequence repeat(SSR) are genomic regions which are comprised of highly variable tandem repeat of two to six DNA nucleotides.SSRs have been found throughout the genomes of many eukaryotes and constitute an abundant source of DNA marker. The level of polymorphim studied thus far has been high and has been greater than that found with RFLPs in maize.several efforts are being made to utilize SSR markers for studies of genetic diversity,germplasm identification,population dynamic and mapping projects.SSRs were abundant in the maize genome and be developed as the second useful molecular marker.\;