Additional file 1.

Characterization of conditional centromere. (A) Conditional centromere does not cause growth defects on glucose. The heterozygous parent of KAY614, containing PGAL1-CEN3 and ura3::HIS3 at the CEN4 locus, was sporulated and tetrads were dissected onto YPD rich medium. (B) Kinetics of galactose-induced chromosome loss. A diploid strain, heterozygous for PGAL1-CEN3 URA3 at CEN3, was grown in YPD to log phase, washed and incubated in YP-galactose, plated to YPD, then phenotyped. The non-repressing sugar raffinose was used in later experiments instead of glucose [40], which is expected to allow more rapid induction of GAL1 promoter activity. (C) Galactose-induced loss of chromosome IV yields unstable 2N-1 phenotype. A diploid strain, heterozygous for PGAL1-CEN3 URA3 at CEN4, was grown overnight in YPD or YP-galactose, then plated to YPD. Most of the small colonies were Ura- and unstable, rapidly reverting to normal growth but remaining Ura-. This is consistent with endoreduplication of the remaining chromosome IV, as observed by Alvaro et al. [29].

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Anders et al. BMC Genetics 2009 10:36   doi:10.1186/1471-2156-10-36