TABLE 3.

Recombination activity (DSB activity) and crossovers on chromosomes I to XVI

ChromosomeSize (kb)aDSB activitybDSB activity/kbcNormalized DSB activity/kbdcMecM/kbNormalized crossovers/normalized DSB activityh
CorrectedfNormalizedg
I2308793.821.071150.631.751.64
II8133,0833.791.062460.320.890.84
III3171,2173.841.081520.541.501.39
IV1,5325,7113.721.044730.340.940.90
V5772,1303.691.032020.391.081.05
VI2701,0673.951.111330.681.891.70
VII1,0914,1043.761.054030.381.061.01
VIII5632,0393.621.011700.451.251.24
IX4401,6633.781.061980.521.441.36
X7462,9834.001.122240.340.940.84
XI6662,4733.711.042510.411.141.10
XII1,8694,6892.510.703830.210.580.83
XIII9243,4243.711.043210.381.061.02
XIV7842,7743.540.992920.411.141.15
XV10914,1123.771.063600.381.061.00
XVI9483,5033.701.042750.330.920.88
  • a The ribosomal RNA gene cluster of about 900 kb was included in the size estimate for chromosome XII. The size of chromosome XII was corrected for the ORFs that were missing on the microarray.

  • b Sum for the whole chromosome of the hybridization ratios (Spo11p-enriched DNA/total genomic DNA) for a 1-kb window moved at 250-bp intervals.

  • c DSB activity divided by chromosome size.

  • d In this column, the data for DSB activity per kilobase were normalized by dividing them by 3.57. This value represents the average DSB activity per kilobase over the whole genome. It was calculated by dividing the sum of the DSB activities for each chromosome (45,857) by the sum of the chromosome sizes (12,861 kb).

  • e Size of the chromosome, based on the Saccharomyces Genome Database.

  • f Since the distance in centimorgans is calculated by genetic crosses, estimates of the genetic length of the chromosomes in the Saccharomyces Genome Database are based on the most distal genetic markers on the chromosomes. Here, the distance in centimorgans was divided by the number of kilobases between the most distal genetic markers (corrected kilobases).

  • g Centimorgans per kilobase (corrected) divided by the average centimorgans per kilobase (corrected) for the whole genome (0.36). The value of 0.36 was obtained by dividing the total centimorgans (4,198) by the sum of the corrected kilobases for the genome (11,593).

  • h Normalized centimorgans per kilobase for each chromosome divided by the normalized DSB activity per kilobase. This ratio is related to the fraction of the DSBs that are resolved as crossovers.