Morphometric Analysis of Animal Hairs In Forensic Investigation
Discipline: Biological Sciences
Subcategory: Education
Session: 3
Room: Exhibit Hall A
Iris Malone - Fort Valley State University
Co-Author(s): Marshal Baalat, Biology Department, 1005 State University Dr., Fort Valley State University, Fort Valley, GA 31030 Desmonet McKnight, Biology Department, 1005 State University Dr., Fort Valley State University, Fort Valley, GA 31030 Seema Dhir, Biology Department, 1005 State University Dr., Fort Valley State University, Fort Valley, GA 31030
Animal hair can be a major contributor when leading investigators to a breakthrough in solving a crime. It is very easily transferred; the victim or the suspect may unknowingly leave hair on the other linking the suspect to the place of the crime. Human and animal hair shaft shows similarities in having an outer covering (cuticle) consisting of scales; an intermediate layer (cortex), which contains the pigment granules imparting the color to hair and an inner core (medulla). At least ten measurements were performed during the morphometric analysis of the hair shaft, medullary diameter, cortex thickness, and scale length on human, cat and deer hair samples. Cuticle scale patterns were investigated using the rapid nail polish method. The guard hair shaft diameter, the medullary index and scale length were measured using image analysis software. Cat haired showed mosaic scale pattern, medullary index (0.63), medulla pattern was uniserial ladder, medullary cavity diameter was 11.7 µm (+ 0.46) and hair shaft diameter was 18.51 µm (+ 0.7). Deer hair showed imbricating flattened to broadly acuminate scale pattern, medullary index (0.90), medulla pattern was lattice, medullary cavity diameter was 199.6 µm (+ 0.1) and hair shaft diameter was 221.6 µm (+ 2.17). Human hair showed imbricate scale pattern, medullary index (0.32), medulla pattern was amorphous, medullary cavity diameter was 24.7 µm (+ 6.9) and hair shaft diameter was 117.0 µm (+ 4.0). Medullary index of > 0.5 indicates an animal hair, whereas < 0.5 is indicative of a human hair. The data obtained in this study suggest that the microscopic analysis of the animal hairs is a valuable diagnostic tool for species identification.
Funder Acknowledgement(s): The support from NSF TIP award # 1818695, PI: Seema Dhir is greatly appreciated.
Faculty Advisor: Seema Dhir, dhirs@fvsu.edu
Role: I prepared the slides for microscopic examination. I did the measurements on hair samples. I took pictures of the hair samples. I gathered data and did data analysis. I prepared the poster.