Mean values and SDs of AUC scores of genes essentiality prediction in 27 bacteria based on Naïve Bayes classifier trained by different integrations of fractal features. The average AUC scores of 27 bacteria are above 0.62. There are 15 (55.56%) bacteria obtaining better predictive performance with fractal features of gene sequences than that of protein sequences and 26 (96.26%) bacteria having better predictive performance by using all fractal features.