Predicting the appearance of a trace donor from the trace DNA left behind at the crime scene in the context of forensic DNA phenotyping is relevant in cases of serious crime that lack suspects, or where all available suspects were excluded by means of forensic STR profiling, as it is in cold cases. Outcomes of DNA-based appearance prediction (together with those from DNA-based prediction of biogeographic ancestry and age not covered by this workshop) can guide police investigation to find trace donors who are not known to the authorities at the start of the investigation.

This workshop will provide in-depth background knowledge on the science and technology of genetic appearance prediction, introduce the most relevant tools, and provide hands-on experience in how to use these tools, in a lively and interactive way with time for question and answers.

Using eye, hair, and skin color, which are the appearance traits for which the science and technology of trace DNA prediction is most established, and which are applied in forensic casework since years already, we will discuss the mostly used DNA markers, DNA tools based on different technologies, prediction models, and prediction tools. We will outline how these tools were developed, discuss the pros and cons of their underlying markers, models and technologies, demonstrate practical steps how to use the prediction tools in deriving trait probabilities from (partial) genotype and sequencing data, and show how to interpret and report the prediction outcomes to the investigating authorities. We will illustrate the use of these tools with various practical examples. Moreover, we will introduce appearance prediction tools that go beyond eye, hair, and skin color. Finally, we will give an outlook on where DNA-based appearance prediction will likely go in the coming years to improve the investigative value.