Non-biased distribution of tomato genes with no counterparts in Arabidopsis thaliana in expression patterns during fruit maturation

We prepared DNA array nylon filters using 10,905 cDNA clones selected from fruit and leaf cDNA libraries of the miniature tomato (Solanum lycopersicum) cultivar, Micro-Tom, as being representative of non-redundant sequences of 37,972 Micro-Tom expressed sequence tags (ESTs). Tomato gene expression during fruit maturation was analyzed using the array filters. Graphs of gene expression patterns were arranged into a 4� 4 array using a self-organizing map algorithm. Using non-redundant sequences generated from 188,024 tomato ESTs, we assigned the cDNA clones on the array filters to 1151 genes that had no counterparts in the Arabidopsis thaliana genome using stringent conditions for e-values of BLAST searching. We found that the expression patterns of these non-Arabidopsis genes were evenly distributed in the self- organizing map, with no statistically significant difference with the distributions of whole genes. These findings suggested that the non-Arabidopsis genes participate in a wide variety of diverse functions during fruit maturation.