Titia Sijen

Introduction

Titia Sijen received her MSc in Plant Breeding at Wageningen University in 1991. After a PhD in molecular plant virology (1997) in Wageningen, two post-doc periods followed: four years at the Free University Amsterdam and six years at the Hubrecht Laboratory. Both the post-doc periods and the PhD centered on the research theme of gene silencing, but the model systems ranged from plants to nematodes. In 2007, Titia decided to change fields and since then she leads the R&D team of the division Biological Traces at the Netherlands Forensic Institute (NFI). Since mid-June 2020 she is part-time professor Forensic Human Biology at the UvA.

Research

As the NFI represents a large casework laboratory (generating for instance over 130,000 DNA profiles a year in more than 52,000 cases), the research team is deeply embedded in the forensic practice. Main research themes relate to methodologies to analyze and interpret complex DNA profiles (complex profiles have multiple contributors, some with such a low-level contribution that not all genotyping information is revealed), RNA-based approaches to assess the cellular origin of biological evidence (to assist when it is questioned what activity took place at a crime scene) and the application of massively parallel sequencing for various forensic purposes (and this is combined with developing bio-informatics tools). The team is part of various international collaborations such as VISAGE (led by Prof Manfred Kayser Erasmus Medical Centre Rotterdam) on using DNA to predict features of an unknown person (or body parts) such as age, biogeographic ancestry and appearance. Molecular, statistical and bio-informatics expertise is combined in various research projects like the association of donor and cell type through RNA-SNPs or generating data to build an expert system to (probabilistically) interpret DNA profiles. Besides technological improvements, much effort is spent on developing interpretation strategies to enable implementation for forensic casework and assist court-going purposes.

Teaching