Rice cDNAs as a model for expressed genes of plants

Large-scale rice cDNA analysis has produced a huge amount of nucleotide sequence information for expressed genes in rice. The genes of cDNA clones putatively identified by similarity search were originally found in many different organisms. However, genes identified at a higher confidence level were found in plants, especially in monocots. This means the sequence information produced in random cloning of rice cDNA is useful for the study of other Gramineae. Further, assigned gene names of cDNAs mapped on linkage group 6 were grouped by their original species. The functions of gene products for 51% of mapped cDNAs were assigned and 67% of them were known in plants. The map information obtained by linking the position of a cDNA locus and its assigned gene function is indispensable for elucidating collinearity of genes among plant genomes.