Validation of candidate markers associated with a phenotype is an essential step in the path toward DNA-based prediction. Due to its high identification potential predicting facial appearance is the central goal of forensic DNA phenotyping. However, the study of facial variation is complicated not only by high polygenicity but also by the complex three-dimensional nature of the human face. MeshMonk is emerging as the standard in predictive facial research, but its application paves the way for two main phenotyping methods. Therefore, our goal was to test the performance of the known candidate facial SNPs starting with global-to-local facial segmentation approach (63 face modules) and facial landmarking approach based on 946 distances derived from 44 landmarks. Association study was conducted for 747 candidate DNA variants selected from literature and 658 3D facial scans of individuals of Polish descent.

Using global-to-local segmentation approach we found 29 SNPs to be significantly associated with 22 segments of the faces in this sample set. The facial landmarking approach identified 27 candidate SNPs to be significantly associated with 60 facial distances. The study identified only 5 DNA variants to be significantly associated with facial features in both approaches. Three of them were associated with the same facial area. The highest number of associations between variants and phenotypes was observed for nose. The study confirms that the currently available data and methodology allow for extensive research on the prediction of facial phenotypes in forensic genetics, but it also confirms that research on this phenotype is technically very demanding and will likely require very large datasets during the predictive modeling phase. 

The data used in this study were collected previously as part of a project funded by NCBR (project no. DOB-BIO10/06/01/2019). The study received funding from the National Science Centre, Poland, grant number 2024/53/B/NZ8/02535.

Authors

• Maria Wróbel (Institute of Forensic Research Faculty of Biology Institute of Zoology and Biomedical Sciences Laboratory of Anthropology Doctoral School of Exact and Natural Sciences Jagiellonian University, Poland)
• Weronika Flis (Faculty of Biology Institute of Zoology and Biomedical Sciences Laboratory of Anthropology Jagiellonian University, Poland)
• Balakrishnan Subramanian (Faculty of Biology Institute of Zoology and Biomedical Sciences Laboratory of Anthropology Jagiellonian University, Poland)
• Tomasz Kupiec (Institute of Forensic Research, Poland)
• Ewelina Pośpiech (Department of Forensic Genetics Pomeranian Medical University in Szczecin, Poland)
• Danuta Piniewska-Róg (Faculty of Forensic Medicine Collegium Medicum Jagiellonian University, Poland)
• Artur Moskała (Faculty of Forensic Medicine Collegium Medicum Jagiellonian University, Poland)
• Iwona Wronka (Faculty of Biology Institute of Zoology and Biomedical Sciences Laboratory of Anthropology Jagiellonian University, Poland)
• Andrzej Ossowski (Department of Forensic Genetics Pomeranian Medical University in Szczecin, Poland)
• Aneta Sitek (Department of Anthropology Institute of Ecology and Environmental Protection Faculty of Biology and Environmental Protection of Łódź, Poland)
• Bożena Wysocka (Central Forensic Laboratory of the Police, Poland)
• Magdalena Spólnicka (Center for Forensic Science University of Warsaw, Poland)
• Magdalena Marcińska (Institute of Forensic Research, Poland)
• Agnieszka Parys-Proszek (Institute of Forensic Research, Poland)
• Haojie Lu (Department of Epidemiology Erasmus MC University Medical Center Rotterdam, Netherlands)
• Ziyi Xiong (Department of Pathology and Clinical Bioinformatics Erasmus MC University Medical Center Rotterdam, Netherlands)
• Manfred Kayser (Department of Pathology and Clinical Bioinformatics Erasmus MC University Medical Center Rotterdam, Netherlands)
• Susan Walsh (Department of Biology Indiana University Indianapolis, United States of America)
• Wojciech Branicki (Institute of Forensic Research Faculty of Biology Institute of Zoology and Biomedical Sciences Laboratory of Anthropology Jagiellonian University, Poland)