X-chromosomal STRs: Metapopulations and mutation rates

Area of Science:

• Forensic genetics
• Population genetics
• Human genetics

Background:

• X-chromosome Short Tandem Repeats (X-STRs) are crucial for complex kinship analysis.
• Limited population haplotype frequency data and mutation rate knowledge hinder X-STR utility.
• Grouping similar population data is essential for reliable parameter estimation.

Purpose of the Study:

• To analyze genetic diversity partitioning for commonly used X-STR loci across global populations.
• To investigate X-STR mutation rates using extensive trio data.
• To enhance the reliability of X-STR analysis in forensic casework.

Main Methods:

• Compiled and analyzed 23,949 X-STR haplotypes from literature and new data.
• Examined genetic diversity and population structure for X-STR profiles.
• Collected segregation data from 2,273 father/mother/daughter trios to determine mutation rates.

Main Results:

• European and East Asian populations show similar X-STR profiles, unlike African, South American, and Asian populations.
• Mutation rates for analyzed X-STR loci varied from 2.68×10⁻⁴ to 1.07×10⁻².
• Male germline mutation rates were 5.2 times higher than female germline rates.

Conclusions:

• X-STR profile similarity varies significantly across global populations, impacting data grouping strategies.
• Established mutation rate ranges provide crucial data for forensic interpretation.
• Findings contribute to more accurate and reliable forensic kinship investigations using X-STRs.