Complex sentence: Biologists have not yet been able to characterize the totality of the cell signaling pathways and regulation of animal and plant cells, and in addition, their genomes display various transcriptional responses and kinetics.
Split into simpler sentences: Biologists have not yet been able to characterize the totality of the cell signaling pathways and regulation of animal and plant cells. In addition, their genomes display various transcriptional responses and kinetics.