sentence: Given the large differences in the numbers of ESTs available among the various cultivars , it is more interesting to compare SNP frequencies , rates , and ratios among cultivars with substantial EST numbers and distinct genetic backgrounds , and differences between the mining results of the three grouped ESTs ( M12 , L7 , and C27 ) and the three sums / averages ( SM12 , SL7 , and SC27 ) of separately mined counterpart individuals .