John Marshall



http://www.its.caltech.edu/~johnmm

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Research Overview

My research focuses on the use of genetically modified (GM) mosquitoes to control malaria in sub-Saharan Africa. I have worked in a mosquito genetic engineering lab, and have developed mathematical models to describe the spread of anti-malaria genes through mosquito populations. I have also commentated on regulatory issues related to GM mosquitoes capable of spreading across international borders, and conducted the first public attutide survey on perspectives of people in Africa to GM mosquitoes for malaria control. Results from this survey suggested people would be supportive of GM mosquitoes that have been shown to work in confined field trials. This led me to become interested in genetic systems that can be confined to partially-isolated populations, and I am currently designing field trials for such systems on islands off the coast of Africa.

I am also part of the malaria modelling group at Imperial College, which is developing large, data-driven models of malaria transmisison in Africa to help inform the World Health Organization and the Gates Foundation on how best to eliminate the disease from the continent. One piece of data that has been missing from these models is how much people travel, which is relevant because people infected with malaria parasites can carry them from one place to another. I have been conducting surveys of human movement patterns to help parameterize these models, and have collected data from Mali, Burkina Faso, Zambia and Tanzania. This data will help to determine the feasibility of local control, and how much interventions must remain in place if malaria is still present in neighboring areas.

I am also interested in science communication and the role of genetic engineering in fighting nutritional defficiencies, improving food security, reducing greenhouse gas emissions and fighting disease. I recently gave a TEDx talk on this subject entitled "If Mother Teresa was a Genetic Engineer."

Selected Publications

Marshall, J. M., M. T. White, A. C. Ghani, Y. Schlein, G. C. Muller, and J. C. Beier, 2013 Quantifying the mosquito’s sweet tooth: Modelling the effectiveness of attractive toxic sugar baits (ATSB) for malaria vector control. Malar. J. 12: 291.

Akbari*, O., K. D. Matzen*, J. M. Marshall*, H. Huang, C. M. Ward, and B. A. Hay, 2013 A synthetic gene drive system for local, reversible modification and suppression of insect populations. Curr. Biol. 23: 671-677.
*Equal contribution

Gatton, M. L., N. Chitnis, T. Churcher, M. J. Donnelly, A. C. Ghani, H. C. J. Godfray, F. Gould, I. Hastings, J. M. Marshall, H. Ranson, M. Rowland, J. Shaman, and S. W. Lindsay, 2013 The importance of mosquito behavioral adaptations to malaria control in Africa. Evolution 67: 1218-1230.

Marshall, J. M., and B. A. Hay, 2012 Confinement of gene drive systems to local populations: A comparative analysis. J. Theor. Biol. 294: 153-171.

Marshall, J. M., and B. A. Hay, 2012 General principles of single-construct chromosomal gene drive. Evolution. 66: 2150-2166.

De Silva, P., and J. M. Marshall, 2012 Factors contributing to urban malaria transmission in sub-Saharan Africa: A systematic review. J. Trop. Med. doi: 10.1155/2012/819563.

Akbari*, O., C. H. Chen*, J. M. Marshall*, H. Huang, I. Antoshechkin, and B. A. Hay, 2012 Novel synthetic Medea selfish genetic elements drive population replacement in Drosophila; a theoretical exploration of Medea-dependent population suppression. ACS Synth. Biol. doi: 10.1021/sb300079h.
*Equal contribution

Marshall, J. M., G. W. Pittman, A. B. Buchman, and B. A. Hay, 2011 Semele: A killer-male, rescue-female system for suppression and replacement of insect disease vector populations. Genetics 187: 535-551.

Marshall, J. M., and B. A. Hay, 2011 Inverse Medea as a novel gene drive system for local population replacement: A theoretical analysis. J. Hered. 102: 336-341.

Marshall, J. M., 2011 The toxin and antidote puzzle: New ways to control insect pest populations through manipulating inheritance. Bioeng. Bugs. 2: 1-6.

Marshall, J. M., 2011 The Cartagena Protocol in the context of recent releases of transgenic and Wolbachia-infected mosquitoes. AsPac. J. Mol. Biol. Biotechnol. 19: 93-100.

Marshall, J. M., 2010 The Cartagena Protocol and genetically modified mosquitoes. Nat. Biotech. 28: 896-897.

Marshall, J. M., M. B. Toure, M. M. Traore, S. Famenini, and C. E. Taylor, 2010 Perspectives of people in Mali toward genetically modified mosquitoes for malaria control. Malaria J. 9: 128.

Marshall, J. M., M. B. Touré, M. M. Traore, and C. E. Taylor, 2010 Towards a quantitative assessment of public attitudes to transgenic mosquitoes: Questions based on a qualitative survey in Mali. AsPac. J. Mol. Biol. Biotechnol. 18: 251-273.

Marshall, J. M., and C. E. Taylor, 2009 Malaria control with transgenic mosquitoes. PLoS Medicine 6: e1000020.

Marshall, J. M., 2009 The effect of gene drive on containment of transgenic mosquitoes. J. Theor. Biol. 258: 250-265.

Marshall, J. M., 2008 A branching process model for the early spread of a transposable element in a diploid population. J. Math. Biol. 57: 811-840.

Marshall, J. M., 2008 The impact of dissociation on transposon-mediated disease control strategies. Genetics 178: 1673-1682.

Marshall, J. M., K. Morikawa, N. Manoukis, and C. E. Taylor, 2007 Predicting the effectiveness of population replacement strategy using mathematical modeling. J. Vis. Exp. 5: 227.

Marshall, J. M., and R. Weiss, 2006 A Bayesian heterogeneous analysis of variance approach to inferring recent selective sweeps. Genetics 173: 2357-2370.