title: Stable Patterns of CENH3 Occupancy Through Maize Lineages Containing Genetically Similar Centromeres.
abstract: While the approximate chromosomal position of centromeres has been identified in many species, little is known about the dynamics and diversity of centromere positions within species. Multiple lines of evidence indicate that DNA sequence has little or no impact in specifying centromeres in maize and in most multicellular organisms. Given that epigenetically defined boundaries are expected to be dynamic, we hypothesized that centromere positions would change rapidly over time, which would result in a diversity of centromere positions in isolated populations. To test this hypothesis, we used CENP-A/cenH3 (CENH3 in maize) chromatin immunoprecipitation to define centromeres in breeding pedigrees that included the B73 inbred as a common parent. While we found a diversity of CENH3 profiles for centromeres with divergent sequences that were not inherited from B73, the CENH3 profiles from centromeres that were inherited from B73 were indistinguishable from each other. We propose that specific genetic elements in centromeric regions favor or inhibit CENH3 accumulation, leading to reproducible patterns of CENH3 occupancy. These data also indicate that dramatic shifts in centromere position normally originate from accumulated or large-scale genetic changes rather than from epigenetic positional drift.
authors.affiliation: Department of Plant Biology, University of Georgia, Athens, Georgia 30602.
authors.forename: Jonathan I
authors.initials: JI
authors.lastname: Gent
authors.affiliation: Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706.
authors.forename: Kai
authors.initials: K
authors.lastname: Wang
authors.affiliation: Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706.
authors.forename: Jiming
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Department of Plant Biology, University of Georgia, Athens, Georgia 30602 Department of Genetics, University of Georgia, Athens, Georgia 30602 kdawe@uga.edu.
authors.forename: R Kelly
authors.initials: RK
authors.lastname: Dawe
mesh_terms: D002503:Centromere / Q000235:genetics*; D047369:Chromatin Immunoprecipitation; D043171:Chromosomal Instability; D018744:DNA, Plant / Q000235:genetics; D018745:Genome, Plant / Q000235:genetics; D007178:Inbreeding; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics; D003313:Zea mays / Q000235:genetics*
chemical_list: D018744:DNA, Plant
keywords: CENP-A; Zea mays; cenH3; centromere specification; epigenetics