John Hogenesch did his graduate work with Dr. Chris Bradfield at Northwestern University working on signal transduction pathways mediated by bHLH-PAS transcription factors. In his thesis work, he discovered five novel mammalian members of the bHLH-PAS family, termed MOP1-5 for members of PAS superfamily (Hogenesch et al., JBC, 1997). Characterization revealed one of the orphans, BMAL1/MOP3, was the partner of a related bHLH-PAS member, Clock, a master regulator of circadian (Hogenesch, et. al, PNAS, 1998). This circuitry comprises the positive arm of the mammalian circadian clock. In 1999 he joined the laboratory of Steve Kay at the Scripps Research Institute and the Novartis Research Foundation as a postdoctoral fellow. At GNF, he worked on the assembly of the complete mammalian transcriptomes (Hogenesch et al., Cell, 2001), as well as on the mRNA characterization of their expression (Su et al, PNAS 2002; Su et al., PNAS, 2004). Current interests include the development of genome wide methodologies for the study of cellular pathways using cDNAs and siRNAs (Conkright et al., Molecular Cell, 2003; Sato et al, Neuron, 2004 ; Willingham et al., Science, 2005; Sato et al., Nature Genetics, 2006; Zhang et al., Cell, 2009; Baggs et al., PLoS Biology, 2009). In 2006, Dr. Hogenesch joined the Department of Pharmacology at the University of Pennsylvania School of Medicine as an Associate Professor, and is now Professor of Pharmacology, Associate Director of the Penn Genomics Institute, and Interim Director of the Institute for Biomedical Informatics. Dr. Hogenesch currently sits on the Scientific Advisory Boards of Qiagen, Bio-Rad, and the Ryan Licht Sang Foundation Medical Committee, and is an advisor to several National Institutes of Health, NIDDK, NCI, NHLBI.