Chapter 4: DNA Matching Technology

4.1 Genetic Relationship Identification

Shared DNA percentages: Parent/Child (50%), Full Siblings (50%), Half Siblings (25%), Grandparent/Grandchild (25%), 1st Cousins (12.5%), 2nd Cousins (3.1%), 3rd Cousins (0.8%).

4.2 DNA Data Formats

Autosomal DNA: SNP array data (600K-700K markers). Y-DNA: STR markers for paternal lineage. mtDNA: Full sequence for maternal lineage. Standards: VCF, GEDCOM 5.5.1, FASTA formats.

4.3 Matching Algorithms

Identity-by-Descent (IBD) segment matching, centiMorgan (cM) calculations, population-specific allele frequencies, ethnicity estimation using PCA analysis.

4.4 Privacy-Preserving Computation

Homomorphic encryption for DNA comparison without exposing raw data. Secure multi-party computation. Differential privacy for aggregated statistics.

4.5 Ethical Considerations

• Informed consent for DNA collection and storage
• Right to genetic privacy and data deletion
• Disclosure of unexpected findings (e.g., non-paternity)
• Protection against genetic discrimination
• Cultural sensitivity in genetic testing