Crossover homeostasis as a function of interval size.

<p>A. Efficiency of meiotic divisions in parallel cultures of wild-type and <i>dmc1 hed1</i> cells. B. Physical map of <i>HIS4::LEU2</i> and adjacent regions of chromosome III showing intervals monitored for crossing-over. Crossovers in interval 1 were monitored by Southern analysis (as in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003978#pgen-1003978-g001" target="_blank">Figure 1A</a>). Crossovers in intervals 2 and 3 were monitored by tetrad analysis. C. 1D Southern analysis of crossing-over in parallel cultures (analyzed in A) of wild-type and <i>dmc1 hed1</i> cells. Asterisk highlights bands diagnostic of non-allelic recombination between <i>HIS4::LEU2</i> and <i>leu2::hisG</i> located ∼25 kb away at the native <i>LEU2</i> locus. D. Quantification of the Southern image shown in (C). Crossover levels at 48 hrs are shown. E. Map distances for intervals 2 and 3 calculated from tetrads sampled from the same cultures analyzed in A, C and D.