Human genome project revealed that human genes are derived from 30,000-40,000 species of genetic loci, which had been estimated as approximately 100,000. The project also promoted devising novel tools that enable us to analyze biological phenomena comprehensively. Microarray technology is a representative of the novel tools in genomics and engages us to explore genome-wide expression levels of genes simultaneously (transcriptome analysis). Here we show transcriptomes obtained from 10 species of cells infected with human cytomegalovirus, as a model virus, by a synthetic DNA microarray system that we have established recently. Our system provides simultaneous and parallel description on alteration of expression of viral and host genes that are represented within a single area on a slide glass. Moreover, we propose a project entitled 'comparative virology on cellular responses of infected hosts' that consists of multiple acquisition and integration of transcriptomes from a combination of several cells and viruses as a panel on the identical platform. The attempt should extract a novel concept in virology from investigation on differences and similarities among influence of a virus on a variety of different cells and conversely among responses of a species of cells against a variety of different viruses.