Application of Familial Y-STR Haplotype Mismatch Tolerance in Genealogy Inference

Area of Science:

• Genetics
• Forensic Science
• Population Genetics

Background:

• Genealogy inference and family lineage investigation rely on genetic markers.
• Y-short tandem repeat (Y-STR) loci are crucial for male lineage studies due to their paternal inheritance.
• Understanding mismatch tolerance in Y-STR mutations is essential for accurate genetic relationship assessments.

Purpose of the Study:

• To establish guidelines for genealogy inference and family lineage investigation.
• To analyze the distribution of mismatch tolerance across 35 Y-STR loci in Chinese Han male lineages.
• To provide a statistical framework for interpreting Y-STR haplotype variations in familial contexts.

Main Methods:

• Selected three Han Chinese lineages with known genetic relationships.
• Employed the YFiler Platinum PCR amplification Kit for typing 35 Y-STR loci.
• Statistically analyzed Y-STR haplotype variations across generations and quantified mismatch tolerance at 1-7 kinship levels.

Main Results:

• Y-STR mutations were lineage-specific, varying in loci and frequency.
• Approximately 66.03% of mutations occurred at rapidly or fast-mutating loci.
• Mismatch tolerance ranged from 0-5 across 35 Y-STR loci (max step 6), with variations based on mutation rates of specific loci.

Conclusions:

• Genealogy inference should consider both zero and multiple mismatch tolerances.
• Prioritize screening of family lineages with 0-3 mismatches across 35 Y-STR loci and 0-1 mismatch on medium/slow loci.
• Exercise caution with lineages showing long steps or including fast-mutating loci in Y-STR analysis.