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Department of Pathology

My research focuses on the human malaria parasite: improving our understanding of the parasite’s basic biology and the impact of this biology on virulence. I use molecular genetics & cell biology to study this important human pathogen.


My first degree was in Natural Sciences at Cambridge, during which time I also participated in the Cold Spring Harbor undergraduate research program in the USA.  I then completed a PhD in Cell Biology at Cancer Research UK, before moving to the Harvard School of Public Health where I held a Charles H. Hood postdoctoral fellowship and studied the epigenetic control of virulence genes in malaria parasites.  During my postdoc I also conducted a field study at the MRC Institute in The Gambia, investigating clinical phenotypes and the expression of virulence genes in patients with malaria. 

Upon returning to the UK I worked briefly as a sub-editor at Nature, then joined the faculty at Keele University where I was a Lecturer and subsequently a Senior Lecturer until spring of 2018.  At Keele I established a research group within the Centre for Applied Entomology and Parasitology (CAEP), gained my Postgraduate Certificate in Teaching & Learning in Higher Education and became a Fellow of the Higher Education Academy.  I taught undergraduate and graduate courses in parasitology and other areas and was awarded a 'superb supervisor' teaching award by the SU.  I sat on the Council of the British Society for Parasitology from 2012 to 2018, serving as the Hon. Communications Secretary 2015-2018. 

In 2018 I moved to Cambridge as an Associate Professor, where my research group is currently funded by a Consolidator grant from the ERC and a Discovery Award from the Wellcome Trust.  At Cambridge I organise the Part II (third year) course in host-pathogen interactions, and teach both undergraduates and graduate (MPhil and PhD) students.

Merrick Lab photo 1


My group studies the human malaria parasite Plasmodium falciparum.  Research interests are centred around DNA biology, particularly the molecular mechanisms underlying DNA replication and cell cycle control in Plasmodium, which replicates by an unusual method called schizogony.  I am also interested in the roles that G-quadruplex DNA and RNA structures may play in the parasite - for example, in silencing and promoting the recombination of a family of key virulence genes called var genes, whose variant expression is under epigenetic control.  In fact, we have discovered that G-quadruplexes and their helicases have more general roles in genome stability/evolution in the malaria parasite, as well as influencing transcript expression at the RNA level.  I have a long-standing interest in epigenetics: my postdoctoral work focussed on a group of deacetylase enzymes called sirtuins which regulate subtelomeric chromatin and virulence gene expression, and are linked to severe malaria in human patients.  We are now studying other epigenetic pathways in Plasmodium, including the novel phenomenon of histone lactylation.

Alongside our research, we are actively involved in science communication, including school visits and participation in the annual Cambridge Festival.  Our latest public engagement project can be found here (website) or as a podcast here: 'We Shall Not Cease From Exploration - The Poetry of Research'.

 Merrick Lab photo 2


Merrick lab news and events



An inaugural meeting of Cambridge-based parasitologists was hosted at the Pathology Department on November 30th.  More than 40 scientists across 7 groups, who study Plasmodium, Toxoplasma and Trypanosoma parasites in the departments of Pathology, Biochemistry, Physics and the Centre for Medical Research, gathered to share their research.  The event was entirely organised by senior postdoctoral researchers from the Rayner and Merrick groups, and was enjoyed by all. 

Oct: A warm welcome to Jemima Swain, who joins the lab as a rotation PhD student in Oct 2023.

Mar: A big thank you to all the lab members who got involved with the annual Cambridge Festival.  On March 25th, the Pathology department hosted 'Changing Pathogens in a Changing World', with many interactive activities for children of all ages.  The Merrick lab was responsible for explaining insect-vector-transmitted disease via 'Hector the Vector'.


Dr Merrick has been visiting KEMRI in Kenya to build a new collaboration with the malaria research group there.  This visit, as well as upcoming work to be led by Dr Noah Onchieku at KEMRI, was funded by a Cambridge-Africa Alborada grant.  The research will focus on mechanisms of drug resistance in malaria parasites.

Feb:  The Merrick lab has been hosting collaborators and epigenetic experts Dr Richard Bartfai and Jonas Gockel, who visited Cambridge from Radboud University in the Netherlands. 

They delivered a 3-day workshop on the new Cut&Tag technique for identifying chromatin protein interactions at genomic scale in Plasmodium.  The workshop was attended by staff from across the Pathology Department (Merrick, Firth and Roychoudhuri labs) and was funded by a small grant from the BBSRC to promote international collaborations. 

Jan: Dr Merrick spent an afternoon in January visiting Trumpington Park Primary School to talk to the children about being a scientist - launching their new topic on 'People who help us'.  It is never too early to encourage young children to aspire to a career in science!


Dec Our newest project idea, funded by the Wellcome Trust from 2023, has been featured in an interview on the long-standing 'Malaria Minute' podcast from the Johns Hopkins Malaria Research Institute in the USA.  More about this exciting new project can be found in Dr Merrick's latest forum article in Trends in Parasitology.

Oct: Congratulations to Dr Noah Onchieku of KEMRI, Kenya, who, together with Dr Merrick, has won an Alborada Grant from Cambridge-Africa.  The grant will support his work investigating proteins that may be involved in the malaria parasite's response to artemisinin.

Oct: Dr Merrick features in the latest 'Say That Again Slowly' podcast from Cambridge University: 'We Shall Not Cease From Exploration - The Poetry of Research'.

Oct: A warm welcome to our new graduate students Megan Armstrong and Lewis Strachan, joining us from Glasgow and Edinburgh universities for a PhD and MPhil respectively.

Sept: Dr Merrick has received a new grant in the first round of Discovery Awards from the Wellcome Trust.  It will fund exciting research on a new concept in Plasmodium epigenetics, and will bring 3 new postdocs and a full-time technician to the lab. 

July: Congratulations to lead author Francis Totanes on the submission of our latest ERC-funded paper on Plasmodium replication - the result of 4 years of hard work, cutting-edge method development and wrangling 63 billion bases of nanopore sequencing data.  This was a great collaboration with the groups of Dr Boemo (Cambridge Pathology) and Dr Bartfai (Radboud University).  Much more is to come from this powerful new method!

July: A warm welcome to Jemima Bittor, who joins us in July and August for a summer studentship on the Cambridge 'Experience Postgrad' programme.  Jemima is approaching the third year of a degree in Biomedical Sciences at Warwick University.

June: Dr Merrick travelled to Marienbad in Czechia for the biennial international conference on G-quadruplexes - the 'G4thering' - to present our recent work.  This research is funded by the Rosetrees Trust & ERC and is led by Dr Holly Craven: it focusses on repurposing G4-binding anticancer drugs as potential antimalarials.


In May 2022 the BioMalPar conference was held in-person at EMBL, Heidelberg, for the first time since 2019.  All of the Merrick-lab postdocs attended, with Drs Holly Craven and Jennifer McDonald presenting posters and Dr Francis Totanes giving a short talk on his project to map replication origins in Plasmodium falciparum using 'DNAscent' nanopore sequencing and ChIP-seq.

May:  On May 3rd, Dr Merrick travelled to Keele University to deliver the keynote lecture at the annual Postgraduate Symposium for Natural Sciences.  The symposium featured short talks and posters presented by students from across the faculty, plus a '3-minute-thesis' competition and a keynote focussing on interdisciplinarity and effective science communication.


At the annual Cambridge Festival, the Cambridge Creative Encounters programme puts on a display of creative work interpreting the work of dozens of Cambridge researchers through film, photography, poetry and drama.  Dr Merrick participated this year: check out her work at the exhibit on New Museum site, Apr 4th-9th, where you can pick up a copy of the collection "We shall not cease from exploration": Words from the field.  Alternatively, find it on the Creative Encounters website.


Dr Holly Craven presented her work on antimalarial drug repurposing at the Cambridge Infectious Diseases symposium on 9th March. The symposium, held in-person for the first time in 3 years, focussed on the pandemic and on Antimicrobial Resistance, with a keynote from Professor Dame Sally Davies.  At the end of March, meanwhile, PhD student Monique Johnson represented the lab at the annual meeting of the British Society of Parasitology held in York.

Feb: Dr Merrick has been invited to join the Editorial Board of the journal Frontiers in Microbiology.


Key publications: 


'Replication origin mapping in the malaria parasite Plasmodium falciparum
Totanes, F.I.G., Gockel, J., Chapman, S.E., Bartfai, R., Boemo, M.A.*, Merrick, C.J.* Nucleic Acids Research (2023).

‘DNA replication dynamics during erythrocytic schizogony in the malaria parasites Plasmodium falciparum and Plasmodium knowlesi
McDonald, J., Merrick, C.J.  Plos Pathogens,
18(6): e1010595. (2022).

'G-quadruplex RNA motifs influence gene expression in the malaria parasite Plasmodium falciparum
Dumetz, F.*, Chow, E.Y.*, Harris, L.M., Umar, M.I., Jensen, A., Chung, B., Chan, T.F.*, Merrick, C.J.*, Kwok, C.K*. Nucleic Acids Research (2021).

Key reviews:

'Checks and Balances? DNA replication and the cell cycle in Plasmodium.'
Matthews, H., Duffy C.W., Merrick, C.J. Invited review, Parasites & Vectors doi:10.1186/s13071-018-2800-1 (2018).

'G-quadruplexes in pathogens: a common route to virulence control?'
Harris, L.M. and Merrick, C.J. PLoS Pathogens 11(2):e1004562. doi: 10.1371/journal.ppat.1004562 (2015).


Other publications: 

‘Effects of the G-quadruplex-binding drugs Quarfloxin and CX-5461 on the malaria parasite Plasmodium falciparum
Craven, H.M., Nettesheim, G., Cicuta, P., Blagborough, A.M., Merrick, C.J.* Int. J. Parasitol: Drugs and Drug Resistance (2023).

'Replication origin mapping in the malaria parasite Plasmodium falciparum
Totanes, F.I.G., Gockel, J., Chapman, S.E., Bartfai, R., Boemo, M.A.*, Merrick, C.J.* Nucleic Acids Research (2023).

'Histone lactylation: A new epigenetic axis for host-parasite signalling in malaria?'
Merrick, C.J. Trends in Parasitology (2022).

‘DNA replication dynamics during erythrocytic schizogony in the malaria parasites Plasmodium falciparum and Plasmodium knowlesi
McDonald, J., Merrick, C.J.  Plos Pathogens, 18(6): e1010595. (2022).

‘Dynamics of DNA replication during male gametogenesis in the malaria parasite Plasmodium falciparum
Matthews, H.; McDonald, J.; Totanes, F.I.G.; Merrick, C.J.  Cellular Microbiology, (2022).

‘The in vivo RNA structurome of the malaria parasite Plasmodium falciparum, a protozoan with an A/T-rich transcriptome’ 
Dumetz, F., Enright, A.J., Zhao, J., Kwok, C.K., Merrick, C.J.  PlosOne, 17(9):e0270863. doi: 10.1371/journal.pone.0270863 (2022).
'Plasmodium falciparum GBP2 is a telomere-associated protein that binds to G-quadruplex DNA and RNA’
Edwards-Smallbone, J., Jensen, A.L., Roberts, L.E., Totanes, F.I.G., Hart, S.R., Merrick, C.J. Front. Cell. Infect. Microbiol. 12:782537 doi: 10.3389/fcimb.2022.782537 (2022).
'G-quadruplex RNA motifs influence gene expression in the malaria parasite Plasmodium falciparum
Dumetz, F.*, Chow, E.Y.*, Harris, L.M., Umar, M.I., Jensen, A., Chung, B., Chan, T.F.*, Merrick, C.J.*, Kwok, C.K*. Nucleic Acids Research (2021).
Editorial. 'Celebrating Microbial Diversity: The Many Cell Cycles of Eukaryotic Microbes'
Merrick, C.J., Absalon, S, Brochet, M, Li, Z, Suvorova, E.S.
Front. Cell. Infect. Microbiol. | doi: 10.3389/fcimb.2021.738994 (2021).

'Hypnozoites in Plasmodium:do parasites parallel plants?’
Merrick, C.J, Trends in Parasitology (2020).

'Conserved associations between G-quadruplex-forming DNA motifs and virulence gene families in malaria parasites.'
Gage, H.L. & Merrick, C.J. BMC Genomics (2020).

‘Parasitic protozoa: unusual roles for G-quadruplexes in early-diverging eukaryotes.’  (REVIEW)
Dumetz, F. & Merrick, C.J. Molecules, special issue on G-quadruplexes & microorganisms. doi: 10.3390/molecules24071339 (2019).

'RecQ helicases in the malaria parasite Plasmodium falciparum affect genome stability, gene expression patterns and DNA replication dynamics.’
Claessens, A., Harris, L.M., Stanojcic, S., Chappell, L., Stanton, A., Kuk, N., Veneziano-Broccia, P., Sterkers, Y., Rayner, J.C., Merrick, C.J. Plos Genetics (2018).

'Checks and Balances? DNA replication and the cell cycle in Plasmodium.' (REVIEW)
Matthews, H., Duffy C.W., Merrick, C.J. Invited review, Parasites & Vectors doi:10.1186/s13071-018-2800-1 (2018).

'ATAC-ing transcriptional mysteries in malaria parasites.’
Merrick, C.J. Preview article, Cell Host & Microbe doi:10.1016/j.chom.2018.03.016 (2018).

'G-quadruplex DNA motifs in the malaria parasite Plasmodium falciparum and their potential as novel antimalarial drug targets.'
Harris, L.M., Monsell, K., Noulin, F., Famodimu, M.T., Smargiasso, N., Damblon, C., Horrocks, P., Merrick, C.J.  Antimicrobial Agents & Chemotherapy

'Perspectives in Parasitology: Plasmodium falciparum.'
Merrick, C.J.  Emerging Topics in Life Sciences 'Perspectives in Parasitology' issue 1(6) 517-523 doi:10.1042/ETLS20170099 (2017).

'Single-molecule Analysis Reveals that DNA Replication Dynamics Vary Across the Course of Schizogony in the Malaria Parasite Plasmodium falciparum.'
Stanojcic, S., Kuk, N., Ullah, I., Sterkers, Y., Merrick, C.J.  Scientific Reports 7:4003 doi:10.1038/s41598-017-04407-z (2017).

'G-quadruplexes: prediction, characterization, and biological application.' (REVIEW)
Kwok, C.K. and Merrick, C.J.  Trends in Biotechnology (2017).

'Recombination events among virulence genes in malaria parasites are associated with G-quadruplex-forming DNA motifs.'
Stanton, A., Harris, L.M., Graham, G., Merrick, C.J.  BMC Genomics 17:859 doi:10.1186/s12864-016-3183-3 (2016).

'SEC-SANS: Size Exclusion Chromatography Combined In Situ With Small Angle Neutron Scattering.'
Jordan, A., Jacques, M., Merrick, C.J., Devos, J., Forsyth, V.T., Porcar, L., Martel, A.  Journal of Applied Crystallography 49 (2016).

'Transfection with thymidine kinase permits bromodeoxyuridine labelling of DNA replication in the human malaria parasite Plasmodium falciparum.'
Merrick, C.J. Malaria Journal 14:490. doi: 10.1186/s12936-015-1014-7 (2015).

'G-quadruplexes in pathogens: a common route to virulence control?' (REVIEW)
Harris, L.M. and Merrick, C.J. PLoS Pathogens 11(2):e1004562. doi: 10.1371/journal.ppat.1004562 (2015).

'Functional analysis of sirtuin genes in multiple Plasmodium falciparum strains.’
Merrick, C.J.,
Jiang, H. R., Skillman, K.M., Samarakoon, U., Moore, R.M., Dzikowski, R., Ferdig, M.T., Duraisingh M.T.  PlosOne 10(3):e0118865. doi: 10.1371/journal.pone.0118865 (2015).

'A quantitative analysis of Plasmodium falciparum transfection using DNA-loaded erythrocytes.'
Hasenkamp, S., Merrick, C.J., Horrocks, P.  Molecular and Biochemical Parasitology 187(2), 117-120 (2013).

‘Epigenetic dysregulation of virulence gene expression in severe Plasmodium falciparum malaria.’
Merrick, C.J., Huttenhower, C., Buckee, C.O., Amambua-Ngwa, A., Gomez-Escobar, N.,Walther, M., Conway, D.J., Duraisingh M.T.  Journal of Infectious Diseases, 205(10), 1593-1600 (2012).

‘Plasmodium Epigenetics: What do we really know?’ (REVIEW)
Merrick, C.J. and Duraisingh, M.T.  Eukaryot Cell, 9(8), 1150-8 (2010).

‘The effect of Plasmodium falciparum Sir2a histone deacetylase on clonal and longitudinal variation in expression of the var family of virulence genes.’
Merrick, C.J., Dzikowski, R., Imamura, H., Chuang, J., Deitsch, K., Duraisingh, M.T. Int. J.Parasitol. 40, 35-43 (2010).

Plasmodium falciparum Sir2: An unusual sirtuin with dual histone deacetylase and ADP-ribosyltransferase activity.’
Merrick, C.J. and Duraisingh, M.T.  Eukaryot Cell, 6(11), 2081-2091 (2007).

‘Heterochromatin-mediated control of virulence gene expression.’ (REVIEW)    
Merrick, C.J. and Duraisingh, M.T.  Mol Microbiol. 62(3), 612-20 (2006).

‘Functional Analysis of Avr9/Cf-9 Rapidly Elicited Genes Identifies a Protein Kinase, ACIK1, that is Essential for Full Cf-9-Dependent Disease Resistance in Tomato.’
Rowland, O., Ludwig, A.A., Merrick, C.J., Baillieul, F., Tracy, F., Durrant, W.E., Fitz-Laylin, L., Nekrasov, V., Yoshioka, H. and Jones, J.D.G.  Plant Cell 17(1), 295-310 (2005).

‘Visualisation of altered replication dynamics after DNA damage in human cells.’  
Merrick, C.J., Jackson, D. and Diffley, J.F.X.  J.Biol.Chem. 279, 20067-20075 (2004).


Online media _________________________________________________________________

"We shall not cease from exploration": Words from the Field.  Cambridge Creative Encounters poetry collection, 2022.

'Rinse and repeat: can mosquito passage ‘reset’ malaria parasites?' Review of Spence et al. Plos Pathogens 2015.
Merrick, C.J. Bugbitten blog of Parasites & Vectors, Aug 2015

'Taking turns: how Plasmodium changes its spots.' Review of Zhang et al. Nature 2014.
Edwards-Smallbone, J. and Merrick, C.J. Bugbitten blog of Parasites & Vectors, Aug 2014.

'Throwing the switch: gametocytogenesis in malaria parasites.' Review of Kafsack et al. & Sinha at al. Nature 2014.
Horrocks, P. and Merrick, C.J. Bugbitten blog of Parasites & Vectors, Apr 2014.

'Malaria virulence genes: Complex control.’ Review of Volz et al. Cell Host & Microbe, 2012.
Merrick, C.J. British Society for Parasitology online journal club, Feb 2012.

 ‘Malaria: An old but pressing problem
Merrick, C.J.  SITN-Flash (Newsletter of the Harvard ‘Science In The News’ Network) World AIDS Day Special Issue on Infectious Diseases, Dec 1 2010.


Science Writing for the General Public ____________________________________________

‘Nature Notes’ (regular column on local ecology)
Sawston Scene village magazine, March 2023 onwards.

"We shall not cease from exploration": Words from the Field.
Cambridge Creative Encounters poetry collection, 2022.

‘Coronavirus, Your questions answered’
Merrick, C.J. & Grimshaw, B  Sawston Scene village magazine, April-May 2020 issue & update in Aug-Sept issue.

‘A Scientist for all Seasons’ (A review of E.O Wilson’s ‘Biophilia’)
Merrick, C.J.   Slightly Foxed, Summer 2014 issue.

‘Adventures in achromatopsia’ (A review of Oliver Sacks’s ‘The Island of The Colourblind’)
Merrick, C.J.   Slightly Foxed, Spring 2013 issue.

‘Honest Jim and the double helix’ (A review of James Watson’s ‘The Double Helix’)
Merrick, C.J.   Slightly Foxed, Autumn 2011 issue.

‘Biophilia for beginners’ (A review of Charles Darwin’s ‘On the Origin of Species’)
Merrick, C.J.   Slightly Foxed, Spring 2011 issue.

‘Tuberculosis: Fighting the Great White Plague.’
Merrick, C.J.  Biological Sciences Review, 21(3), 2009.

Teaching and Supervisions


I lead the Host-pathogen interactions module in the Part II (third year undergraduate) Pathology course.  I host undergraduate research projects annually in this option, and also take Masters and PhD students.

Research supervision: 

Please contact me by email if you are interested in PhD or postdoctoral work in my group.  If funded positions are available, they will be advertised here, otherwise I am happy to discuss possible projects for fellowship applications with qualified candidates. 

Current lab members:

  • Dr Francis Totanes, postdoc, from July 2018
  • Dr Holly Craven, postdoc, from Oct 2019
  • Dr Ibtissam Jabre, postdoc, from Feb 2023
  • Dr Nana Efua Andoh, postdoc, from Feb 2023
  • Dr Haddijatou Mbye, postdoc, from Mar 2023
  • Dr Juliana Naldoni, technician, from Feb 2023
  • Monique Johnson, PhD student, 2020-2024
  • Megan Armstrong, PhD student, 2022-2026
  • Jemima Swain, PhD rotation student, 2023
  • Nelly Wolman, undergraduate project student, 2023-2024

Lab retreat 2021,  Lab Christmas lunch 2018.   

A French/American themed, socially-distanced outdoor leaving do, 2020.

Previous lab members:

  • Technicians
  • Dr Rachana Ramarao, 2021-2023
  • Anders Jensen, 2018-2021 (subsequently deputy lab manager, Cambridge Pathology Dept.)
  • Dr Lisa Rump, 2017-2018
  • PhD students
  • Dr Linda Onyeka Anagu, 2015-2019 (secondment from Nnamdi Azikiwe University, Nigeria, subsequently AREF postdoc fellow)
  • Dr Ashley J. Jordan, 2012-2016 (subsequently postdoc at Institut Laue-Langevin Grenoble).
  • Masters students
  • Cambridge:
  • 2022-2023: Lewis Strachan, MPhil (subsequently PhD student at CIMR)
  • 2019-2020: Louise DeThomasson, MPhil
  • (Keele, 2012-17):
  • 6 MSc students on programmes including MSc in Molecular Parasitology and Vector Biology, MSc in Scientific Research Training abroad, and ERASMUS.  3 students (Adriana Adolfi, Rinal Sahputra & Pamela Veneziano-Broccia) progressed to PhDs at LSTM, Manchester and Trieste.
  • 1 MPhil, Dr Katelyn Monsell - intercalated year in research during medical training at Keele Medical School.
  • Undergraduates
  • Cambridge:
  • 2022-23: Emmie Savory (Medical degree 2023)
  • 2021-22: Kate Tilley (Natural Sciences project student); Jemima Bittor ('Experience Postgrad' summer student 2022)
  • 2020-21: Daniel Nash (Pathology Society scholarship summer student, 2021, subsequently PhD student at Cambridge)
  • 2019-20: Christopher Cannon (Natural Sciences degree 2020, subsequently PhD student at Nottingham)
  • 2018-19: Lydia Roberts (Medical degree 2019); Hunter Gage (U. Madison SCORE programme summer student; subsequently Medical school at UCSD)
  • Keele (2011-2017):
  • 20 undergraduate students, including 4 progressing to PhD/MSc degrees.
University Associate Professor
Division of Microbiology and Parasitology
Dr Catherine J. Merrick

Contact Details

208, Molteno Building,
Department of Pathology,
Tennis Court Road,
CB2 1QP.
01223 333330
Takes PhD students
Not available for consultancy