Mexican mestizo population sub-structure: effects on genetic and forensic statistical parameters

Area of Science:

• Population Genetics
• Forensic Science

Background:

• Mexican mestizos represent an admixed population group.
• Understanding population substructure is crucial for accurate genetic and forensic analyses.

Purpose of the Study:

• To investigate the effects of population substructure on genetic and forensic parameters in Mexican mestizos.
• To evaluate the forensic efficiency of 15 short tandem repeat (STR) loci.

Main Methods:

• Analysis of 15 STR loci (CODIS, D2S1338, D19S433) in 1,640 unrelated Mexican mestizos.
• Determination of allele and genotypic frequencies.
• Testing for Hardy-Weinberg equilibrium and linkage disequilibrium.
• Genetic population stratification analysis.

Main Results:

• Significant departure from Hardy-Weinberg expectation observed in 12 out of 15 loci, with an excess of homozygotes.
• Apparent linkage disequilibrium found in 13 of 92 locus pairs.
• The Mexican mestizo population is substructured into three subgroups, which are in equilibrium.
• High forensic efficiency (discrimination capacity of 1/10^18) using the 15 STR loci.

Conclusions:

• The 15 STR loci are validated for forensic identity and parentage testing in Mexican mestizos.
• Population stratification necessitates the application of inbreeding coefficient corrections in forensic calculations.
• The study provides a robust tool for genetic variation analysis in this population.