Maize Centromere Structure and Evolution: Sequence Analysis of Centromeres 2 and 5 Reveals Dynamic Loci Shaped Primarily by Retrotransposons

摘要: We describe a comprehensive and general approach for mapping centromeres present detailed characterization of two maize centromeres. Centromeres are difficult to map analyze because they consist primarily repetitive DNA sequences, which in the tandem satellite repeat CentC interspersed centromeric retrotransposons (CRM). defined epigenetically by histone H3 variant, CENH3. Using novel markers derived from centromere repeats, we have mapped all ten onto physical genetic maps maize. were able completely traverse 2 5, confirm fluorescence situ hybridization (FISH), delineate their functional regions chromatin immunoprecipitation (ChIP) with anti-CENH3 antibody followed pyrosequencing. These differ substantially size, apparent CENH3 density, arrangement repeats; larger than rice characterized date. Furthermore, 5 consists distinct domains that separated several megabases. Succession classes is evidenced fact elements belonging recently active recombinant subgroups CRM1 colonize day centromeres, while ancestral also found flanking regions. abundant CRM non-CRM inserted near these create historical record location, show fluid genomic whose borders heavily influenced interplay epigenetic marks. propose CRMs may be involved removal (specifically CentC), invasion retrotransposons, local repositioning