A hypervariable STR polymorphism in the complement factor I (CFI) gene: Asian-specific alleles.

Area of Science:

• Population genetics
• Forensic science
• Human genetics

Background:

• The human complement factor I (CFI) gene plays a crucial role in the immune system.
• Short tandem repeat (STR) polymorphisms are widely used in forensic genetics for individual identification.
• Understanding genetic diversity across populations is essential for accurate forensic applications.

Purpose of the Study:

• To investigate a novel STR polymorphism in intron 7 of the human CFI gene.
• To analyze the allele frequencies and distribution of this STR in diverse ethnic populations.
• To evaluate the utility of this STR marker for forensic individualization.

Main Methods:

• Genotyping of 637 DNA samples from African, German, Thai, and Japanese populations.
• Analysis of STR polymorphism in intron 7 of the CFI gene.
• Classification of alleles into size-based groups (L and H) and association with specific gene variants (CFI*Ah).

Main Results:

• A total of 41 alleles were identified for the CFI gene STR polymorphism.
• A distinct group of 16 alleles (Group H) was found exclusively in Thai and Japanese populations.
• High heterozygosity values (0.89-0.93) indicate significant genetic variation within populations.

Conclusions:

• The identified STR polymorphism in the CFI gene exhibits significant population-specific characteristics.
• The 'H' allele group's presence in Asian populations and association with CFI*Ah provides valuable discriminatory power.
• This STR marker serves as a useful supplementary tool for forensic DNA profiling and population studies.