Universiteit Leiden

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Manon de Visser


M.C. de Visser MSc
+31 71 527 4882

Together with her co-workers at IBL and Naturalis Biodiversity Center, Manon aims to unravel the evolutionary mysteries underlying the enigma of balanced lethal systems. Her focus is on Triturus newts. Furthermore, Manon regularly appears in the media. She has a passion for science communication and nature conservation.

More information about Manon de Visser

Brief biography

In 2015 Manon obtained her BSc degree in Biology at the University of Utrecht after concluding a research essay and thesis focused on the influence of global warming on the development of sea turtle eggs. In 2018 she obtained her MSc degree in Biology at the University of Wageningen, where she invested in a double specialization and concluded two Major thesis and two Major internship projects. For one of her theses, Manon studied whole-genome re-sequence data of the pygmy hog (Porcula salvania), the smallest and most threatened pig species in the world.

Before her PhD started, Manon worked for a molecular research agency and she worked as an ecological consultant within the Netherlands, doing a lot of round the clock fieldwork. Also, she has been volunteering over the years, for instance at zoos and NGOs, in order to raise awareness regarding biodiversity loss and the need for conservation efforts for threatened and vulnerable species. In her current work related to amphibians, Manon also spends a lot of time on education, communication and public outreach.

‘I am fascinated by the resilience of nature, even though it is clear the natural world also needs our help. I believe that the successes achieved in investigating and protecting the natural world - two of our greatest duties, in my opinion - are mostly manifested by thinking out of the box and working together.’ After her PhD and current postdoc project, in which she focuses on the evolution of balanced lethal systems in Triturus newts, Manon aims to pursue a career in conservation genomics, evolutionary biology, and/or science communication.


Salamanders are relatively understudied in the field of genomics due to their gigantic genome sizes. Nevertheless, the Wielstra lab aims to unravel the evolutionary enigma that is ‘the balanced lethal system’ by looking at the DNA of Triturus newts as a case study. Namely, in all species of Triturus 50% of the eggs die before hatching, no matter the circumstances. This means half the reproductive effort is consistently wasted!

In a balanced lethal system, diploid individuals require two different versions of a chromosome in order to survive: this means all heterozygotes get to live (50%), whilst homozygotes die (50%, as observed in the newts). This seems to defy evolutionary theory as natural selection should generally not allow for the existence of such a disadvantageous phenomenon.

Manon's research includes identifying the genetic lethal factors and investigating their evolution. By applying phylogenetic approaches, she is studying the most likely ancestral constitution of the deviant chromosome pair in Triturus millions of years ago. She uses a sequence capture technique (Hyb-Seq) to overcome the current challenges of working with relatively large genomes. Also, she investigates how well the sequence capture technique performs in other salamanders, apart from the Triturus studies.


  • Selected as 'Face of Science 2023' by the Royal Netherlands Academy of Arts and Sciences (KNAW), The Youth Academy (De Jonge Akademie) and NEMO Kennislink, after being nominated by Associate Professor and marine biologist Dr Lisa Becking
  • 1st prize for one-minute pitch at the Netherlands Society of Evolutionary Biology PhD & Postdoc meeting 2021 (NLSEB2021), for the pitch: "The balanced lethal system in Triturus: an evolutionary trap!"
  • 3rd best oral presentation at the Programming For Evolutionary Biology Conference 2021 (miniPEB2021), Freie Universität Berlin, for the talk: "Studying the lethality and evolutionary origin of the balanced lethal system in Triturus newts".
  • 1st prize for oral presentation within subtheme: “Global Health - Humans and Animals" at the University of Copenhagen EuroLeague of Life Sciences (ELLS) Student Conference 2017, for the MSc project "The Importance of Genomics for the Conservation Management of the Critically Endangered Pygmy Hog (Porcula salvania)".
  • Best oral presentation at the Benelux International Society of Applied Ethology (ISAE) meeting 2016, for the MSc project "The effect of exposure to visitors on stress in the critically endangered blue-eyed black lemur (Eulemur flavifrons) and other primate species at Apenheul Primate Park, the Netherlands."


  • Science
  • Instituut Biologie Leiden
  • IBL Animal Sciences

Work address

Sylviusweg 72
2333 BE Leiden
Room number 3.5.17



  • Genotypical (= naam van het bedrijf) Eigen bedrijf / ZZP / eenmanszaak
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