highly significantP < 0.001
Although the sample sizes were reduced, the significance of the associations reported remained highly significant: The odds ratio calculated from alignments between A. thaliana and A. lyrata orthologous was 1.17 with a Z score of 16.23 ( P < 0.001), whereas the tests calculated on alignments between rice and B . distachyon gave an odds ratio of 1.18 ( Z = 23.88; P < 0.001) and 1.45 ( Z = 8.23; P < 0.001) for rice low-GC and high-GC data sets, respectively ( table 2 ).