title: Pedigree analysis of plasmid segregation in yeast.
abstract: We have used pedigree analysis to investigate the mitotic segregation of circular and linear DNA plasmids in Saccharomyces cerevisae. Circular ARS plasmids, which bear putative chromosomal replication origins, have a high segregation frequency and a strong bias to segregate to the mother cell at mitosis. The segregation bias explains how the fraction of plasmid-bearing cells can be small despite the high average copy number of circular ARS plasmids. Linear ARS plasmids do not show strong segregation bias, nor does the 2 mu ori-containing plasmid YEp 13, when it is present in strains containing intact 2 mu circles. In the absence of endogenous 2 mu circles, YEp 13 behaves like an ARS plasmid, showing a strong maternal segregation bias. The presence of a centromere on circular ARS plasmids eliminates segregation bias. We discuss a model for plasmid segregation, which explains these findings and the possible biological significance of mother-daughter segregation bias.
mesh_terms: D004247:DNA / Q000032:analysis*; D004270:DNA, Circular / Q000032:analysis*; D008433:Mathematics; D010957:Plasmids; D012441:Saccharomyces cerevisiae / Q000235:genetics*
chemical_list: D004270:DNA, Circular; D004247:DNA