Forensic evidence based on mtDNA from dog and wolf hairs

Area of Science:

• Forensic Science
• Molecular Biology
• Genetics

Background:

• Forensic investigations often rely on trace evidence, such as shed hairs.
• Distinguishing between closely related species like domestic dogs and wolves can be challenging using traditional methods.

Purpose of the Study:

• To evaluate the utility of mitochondrial DNA (mtDNA) sequencing for analyzing single shed hairs in forensic casework.
• To determine if mtDNA analysis can aid in suspect identification or exclusion and species identification in criminal investigations.

Main Methods:

• Mitochondrial DNA (mtDNA) sequencing was performed on a 79 bp segment of the control region from shed hair samples.
• Sequenced mtDNA was compared against a comprehensive database of domestic dog and wolf populations.
• Analysis was conducted on evidence from six diverse forensic cases, including murder, robbery, theft, and poaching.

Main Results:

• Mitochondrial DNA analysis enabled the exclusion of all eight suspects in three separate murder investigations.
• A rare mtDNA sequence variant linked two murder cases and indicated the specific dog breed involved.
• Evidence from theft and bank robbery cases was successfully linked to suspects; suspected wolf poaching was identified as dog origin.

Conclusions:

• Single shed hairs from domestic pets are suitable for reliable mitochondrial DNA analysis.
• The described mtDNA sequencing method is a valuable and effective tool for forensic investigations, aiding in suspect exclusion, case linkage, and species identification.