Investigative genetic genealogy: Current methods, knowledge and practice

Area of Science:

• Forensic Science
• Genetics
• Genealogy

Background:

• Investigative genetic genealogy (IGG) is a rapidly advancing forensic discipline.
• IGG utilizes dense single nucleotide polymorphism (SNP) data for relationship inference.

Purpose of the Study:

• To describe the process of using SNP data for inferring distant relationships in forensic investigations.
• To review methods for relationship matching and SNP analysis in identifying criminal suspects or missing persons.
• To examine the effectiveness, operational limits, and future validation of IGG technologies and data.

Main Methods:

• Analysis of dense SNP data (over 500,000 markers) to infer genetic relatedness.
• Review of relationship matching and SNP analysis techniques in a forensic context.
• Investigation of direct-to-consumer (DTC) genetic ancestry testing company methods and IGG provider operations via questionnaire.

Main Results:

• Dense SNP data enables inference of genetic relatedness beyond first cousins.
• IGG methods are applied to identify individuals in criminal investigations and locate missing persons.
• Current knowledge on proprietary algorithms is reviewed, alongside operational summaries from IGG providers.

Conclusions:

• There is a critical need to understand the models and technologies underpinning forensic IGG.
• Further research is required for the forensic validation of IGG methods and data.
• This review synthesizes current knowledge and suggests future research directions for IGG in forensic science.