Dr. DeJong’s research focuses on the biology of invertebrates, especially parasites and their hosts, from ecological, evolutionary, and genetic perspectives. He has long-standing interests in molluscs (snails, mussels, etc.) and in schistosomes, a group of parasites that includes species that cause human disease in many developing countries, and also includes species that are found in birds and mammals all over the world. He is currently interested in community assemblages of bacteria and bacteriophages within invertebrate hosts.

Dr. DeJong enjoys reading, attending concerts, working in the yard, hiking, and camping. He and his wife, Jennifer Knox DeJong, have been involved in ministry to college students since 2001, and are parents of two children.


  • B.S. in Biology, Calvin College, 1994
  • M.S. in Zoology, Michigan State University, 1997
  • Ph.D., University of New Mexico, 2003

Courses taught


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Academic Interests

Before coming to Calvin, Dr. DeJong was a research scientist at the National Institutes of Health near Washington D.C. There he investigated, at the genetic level, the relationship between malaria parasites and the mosquitoes that transmit them. During his Ph.D. studies, Dr. DeJong participated in the first global genetic study of the parasite Schistosoma mansoni and led the most complete genetic study of its snail host, Biomphalaria. He has published more than 25 papers in the areas of parasitology, immunobiology, ecology, and evolution and has teaching experience at several institutions of higher learning.


Studying the interactions of Schistosoma parasites with their snail hosts as well as aquatic invertebrate ecology. 

Observing the interactions between bacteriophages (viruses that infect bacteria) and their bacteria hosts. The project utilizes genomics to observe bacteriophage abundance, important genes within bacteria for these relationships and horizontal gene transfer events.

Selected publications

  • Molina-Cruz, A, RJ DeJong, C Ortega, A Haile, E Abban, J Rodrigues, G Jaramillo-Gutierrez, and C Barillas-Mury. 2012. Some strains of Plasmodium falciparum, a human malaria parasite, evade the complement-like system of Anopheles gambiaemosquitoes. Proceedings of the National Academy of Sciences. ePrint, May 23, 2012, doi:10.1073/pnas.1121183109
  • Pope, W.H., CM Ferriera, D Jacobs-Sera, RC Benjamin, Ariangela J Davis*, Randall J. DeJong, SCR Elgin, FR Guilfoile, MH Forsyth, Alexander D. Harris*, SE Harvey, LE Hughes, PM Hynes, AS Jackson, MD Jalal, EA MacMurray, CM Manley, MJ McDonough, JL Mosier, Larissa J. Osterbaan*, HS Rabinowitz, CN Rhyan, DA Russell, MS Saha, CD Shaffer, SE Simon, EF Sims, IG Tovar, EG Weisser, John T. Wertz, KA Weston-Hafer, KE Williamson, B Zhang, SG Cresawn, P Jain, M Piuri, WR Jacobs Jr., RW Hendrix, GF Hatfull. 2011. Cluster K Mycobacteriophages: Insights into the Evolutionary Origins of Mycobacteriophage TM4. PLoS One 6(10): e26750. doi:10.1371/journal.pone.0026750
  • Lotfy,WM, SV Brant, RJ DeJong, TH Le, A Demiaszkiewicz, RPVJ Rajapakse, VBVP Perera, JR Laursen, and ES Loker. 2008. Evolutionary origins, diversification, and biogeography of liver flukes (Digenea, Fasciolidae). American Journal of Tropical Medicine and Hygiene 79: 248-255.
  • Zhang, SM, H Nian, Y Zeng, and RJ DeJong. 2008. Fibrinogen-bearing protein genes in the snail Biomphalaria glabrata: Characterization of two novel genes and expression studies during ontogenesis and trematode infection. Developmental and Comparative Immunology 32: 1119-1130.
  • Molina-Cruz, A. RJ DeJong, B Charles, L Gupta, S Kumar, G Jaramillo-Gutierrez, and C Barillas-Mury. 2008. Reactive oxygen species modulate Anopheles gambiae immunity against bacteria and Plasmodium. Journal of Biological Chemistry 283: 3217-3223.