Pedigree-Based Estimation of Y-STR Mutation and Male Differentiation Rates: Application to Historical Remains...

Area of Science:

• Forensic Genetics
• Population Genetics
• Human Genetics

Background:

• Y-chromosomal short tandem repeats (Y-STRs) provide high differentiation rates beneficial for forensic and genealogical casework.
• Their utility in historical remains identification casework remains underexplored.

Purpose of the Study:

• To analyze the differentiation rates and mutation patterns of Y-STRs within pedigrees.
• To assess the reliability of pedigree analysis for estimating Y-STR mutation rates.
• To evaluate the impact of Y-STR differentiation on identifying patrilineal relationships across varying degrees of relatedness.

Main Methods:

• Conducted a pedigree analysis of 366 males across 183 pedigrees, examining 27 Y-STR loci using the Yfiler Plus kit.
• Defined differentiation rate as the proportion of pairs with allelic differences at specific meiotic separations.
• Estimated locus-specific mutation rates from pedigree data.

Main Results:

• Pedigree-based mutation rates aligned with published father-son values for most loci, with three exceptions (DYS389II, DYS449, DYS570).
• The probability of differentiating male relatives reached 60.1%, consistent with prior studies.
• Strong agreement between father-son and pedigree-based mutation rates validates pedigree analysis for rate estimation.

Conclusions:

• High Y-STR differentiation aids in distinguishing unrelated individuals and reducing false inclusions.
• Accumulated mutations over many generations can obscure distant patrilineal relationships, increasing false exclusion risks.
• Findings are valuable for interpreting Y-STR haplotypes, particularly for historical remains identification.