PhD Defense Margriet Oomen

Margriet Oomen will defend her PhD thesis entitled 'Spatial Populations with Seed-bank' on November 18th 2021.


margrietoomenMargriet's promotors are Frank den Hollander (Leiden University) and Andreas Greven (Friedrich-Alexander University Erlangen-Nürnberg).


The PhD defense will start at 12.30 hrs in the Academy Building (Rapenburg 73, 2311 SL Leiden). Due to the COVID rules, access is only permitted for a limited audience. The defence will be live streamed on the Leiden University website.


As from December 2021 Margriet will work as a project engineer at Witteveen+Bos in their data-science group.



In populations with a seed-bank, individuals can temporarily become dormant and refrain from reproduction until they can become active again. The repository of all dormant individuals in the population is called the seed-bank. Seed-banks are observed in many taxa, including plants, bacteria and other micro-organisms. Typically, they arise as a response to unfavourable environmental conditions. In this thesis we study the effect of a seed-bank on the genetic diversity in a population where individuals live in different colonies. The individuals in the population carry one of two gene types, and can be either active or dormant. Active individuals can migrate between different colonies, resample and become dormant. Dormant individuals can only become active: they do not migrate and they do not reproduce themselves. The model is described by a system of interacting Fisher-Wright diffusions. In the first part of this thesis, we analyse the system of interacting diffusions when the underlying spatial structure is a countable Abelian group. In the second part we analyse the system when the underlying spatial structure is the hierarchical group. We show that in both cases the seed-bank enhances the genetic diversity in a population. If the individuals can become dormant for long enough times, the seed-bank can even prevent that a gene type becomes extinct.


Margriet received the cum laude distinction for her thesis, you can read more about this here.

You can read the thesis here.

When: Thursday November 18th, 2021
Time: 12:30 - 13:15
Where: UL


Leiden University, Academy