| Abstract: | The frequency and average amount of copy number per genome were defined for standard and a number of new variants of BamHI 5'-NTS RFLP from populations of Moscow, Riga and individuals with Down syndrome. It was demonstrated that the populations studied differ neither in population frequency nor in the average amount of copy number of the variants. New variants were detected in the EcoRI 3'-NTS RFLP system and their amplification, as well as discordance among MZ twins. Possible target for methylation in the HindII site of 3' end of 28S rRNA gene was revealed. Analysis of data obtained demonstrated inefficiency of using the RFLP systems in systematic mapping of NOR-chromosomes. Our data also suggested a possible role of amplification of one copy repeated unit rRNA genes in their evolution. |
