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Centre for the Forensic Sciences Blog



My Master’s Dissertation: Secondary Transfer of Trace DNA

uctzsh017 April 2016

One of the forefronts of forensic DNA research is the secondary transfer of trace DNA. Secondary transfer is an example of passive transfer and occurs when one person’s DNA is deposited onto an object by someone (or something) else. Trace DNA is usually found in small amounts from sources such as skin cells which are deposited on an object after it has been touched or casually handled.  If this object becomes evidence in a criminal investigation, the possibility of placing an innocent individual at the crime scene arises. The occurrence of secondary transfer of trace DNA has only come to light in the last several years and so there is currently not much known about it. The study I have proposed for my dissertation will evaluate if relative pressure of contact has any effect on the transfer of trace DNA. Knowing this will reveal what factors are required for secondary transfer to happen, and help uncover its relevance in a forensic context.

Tobias, Samuel

Me dusting for prints in a CSI practical session

Forensic DNA technology has progressed to the point where genetic profiles can be generated from samples where only a few cells are present. For this reason, steps have to be taken to prevent any contamination of the samples. The research undertaken by the UCL Centre for Forensic Science is carried out in the collaborative UCL division of Biosciences, UCL CFS and UCL Institute of Archaeology Ancient DNA facility. The ultra-clean lab provides a safe and contamination-free space to extract the DNA from the low-template samples of trace DNA.

As the use of DNA in forensic science continues to expand, the need for scientific literature on the subject will only grow as well. The occurrence of secondary DNA transfer is on the leading-edge of forensic biology research; therefore, my ultimate goal is to create a publishable study that will contribute to the field of forensic DNA research in a beneficial way.

MSc module assessment – Practices of Crime Scene Investigation and Expert Testimony

uctzreg15 April 2016

Last week, we held the first part of the assessment of our MSc students on the Practices of Crime Scene Investigation and Expert Testimony module, aka CSI. The MSc students were given a fictitious crime scenario which they used to ask additional questions and then locate and collect items of evidence at a mock crime scene. This was my first year assisting on this module as a TA and I found it a very fascinating experience. Throughout the module, the students have practicals on different areas of the crime scene investigation including, documentation, packaging, evidence recovery and contamination-minimisation procedures. These are to prepare for this final mock crime scene and to give them an idea of what to expect when approaching and examining a crime scene.


The students during their practicals

With identical training, one might expect the students to address the crime scene challenge in the same way. However, seeing the different approaches that each student takes and the different thought processes that go on has been very interesting. It is remarkable how some items of evidence or questions to ask for further information are more obvious to some people than others. It also shows that some people have a natural knack for this type of work compared to others. Next week is the second part of the assessment in which the students give evidence on their crime scene examination in a mock courtroom setting…I wonder how varied their testimonies will be?

A Forensic Science Experience

uctzmsc11 April 2016

What is forensic science? Many people would reply to that by saying something along the lines of “science as it pertains to the law”—and they are not wrong; but they are not giving the full definition of forensic science either. I was one of these people.

Before attending UCL for the Master’s degree in Crime and Forensic Science, I studied Medical Biochemistry. I went from studying the proteins and biochemical processes that make humans, humans…to a mixture of psychology, law and forensic science utilised in criminal investigations.

Getting used to this new way of thinking was the hardest aspect of this change in subject, and sometimes it still is. But it is worth it! Yes, it required that I had to catch up on a lot, from the basics to the content of the lectures (and beyond!), but I enjoyed doing it. I cannot complain about the reading; after all, it is a postgraduate degree and having no background in this area meant that I had to work twice as hard. Literally, forensic science (and food) was all I thought about. It had trapped me in an infinite loop of information—but so did proteins, so I knew I made the right choice in pursuing an additional dream!

cartooncrimelab Forensic science is a broad topic, and the CSI shows on TV only capture a small portion of what it actually entails. My advice is, if you want to go into forensic science and/or crime scene investigation, do not rely on the CSI shows to give an accurate depiction. Indeed, they are helpful as an introduction to forensic science—but just like the definition, the shows do not cover the whole arena. Undertaking a 12 month course on a given topic without a reality-check may leave you feeling disappointed; however, you get to learn about a lot of  fun and unimaginable topics by pursuing a forensic science degree. I certainly did, and I am sure you can too!

Side-note: not all of those high-tech machines you see on TV exist…but there are some really awesome ones that do—refer to a previous post on https://blogs.ucl.ac.uk/forensic-sciences/cfs-seminar-series-mike-ferguson-cast/.

Forensic Osteology Module – An MSc Student Perspective

uctzsh025 March 2016

On the first day of class, we were examining cadavers. On the second day of class, I was dissecting an arm. On the third day of class, we were boiling, or as it’s called, macerating, a defleshed limb. For the forensic osteology module, we were thrown into the deep end right from day one.


In this module, we learned what the role of a forensic osteologist entails, and their place in a criminal investigation. We also learned the anatomy of the human skeleton, with each student in the class being provided one at their desk for every lecture. Being able to hold the physical bone, instead of just looking at pictures really helps to solidify what you’re learning, as well as be more engaged with the content. We didn’t just work with bones though; we also learned how the whole body can aid a forensic investigation throughout all stages of the decomposition process.

The course culminated with a case study where, in small groups, we were given a bag filled with remains and extra pieces of evidence. Our task was to not only create a biological profile of who these bones belonged to (sometimes more than one person), but also suggest how they died and any other information we could infer from the evidence. This project helped to synthesize the material, and put into practice what I had learned throughout the course.

Forensic osteology was definitely one of my favourite modules this term, no bones about it.