Epigenetic Remodeling of Meiotic Crossover Frequency in Arabidopsis thaliana DNA Methyltransferase Mutants
Figure 3
Decreased pericentromeric crossovers in met1–3.
(A) Physical map of chromosome 3 with overlaid genes/Mb (green), cM/Mb (red) and DNA methylation (blue) plots. The dotted, horizontal red line indicates the cM/Mb weighted mean. Outer vertical black lines indicate the position of FTL transgene insertions that define CEN3. Inner vertical black lines indicate the position of centromeric markers analyzed in Figure 2. The vertical magenta line indicates the centromere. (B) Chromosomes heterozygous for trans-linked FTL332 (eYFP) and FTL2536 (DsRed) transgenes, which flank the centromere (black circle) segregating through meiosis-I and –II in the absence (left) or presence (right) of a CO within CEN3. (C) Fluorescence micrographs of qrt1–2 pollen showing patterns of inheritance associated with (tetratype) or without (parental ditype) a CO within CEN3. BF shows bight field illumination and R and G indicate red and green UV fluorescence. (D) CEN3 genetic map lengths for naïve wild type (Col), MET1, met1–3+/−, met1–3−/− segregants and self-fertilized met1–3−/− measured by qrt1–2−/− tetrad counting. (E) Southern blotting and hybridization analysis of CEN180 following digestion of genomic DNA using DNA methylation sensitive HpaII. DNA was prepared from CEN3 qrt1–2−/− individuals whose measured genetic distance in cM is indicated above the blot in blue in addition to their met1–3 genotype. See also Table S3.