Sequence variation of a hypervariable short tandem repeat at the D12S391 locus

Area of Science:

• Forensic Genetics
• Population Genetics
• Molecular Biology

Background:

• Short tandem repeats (STRs) are crucial genetic markers used in human identification.
• The D12S391 locus is a Y-chromosome STR previously characterized.
• Understanding STR allele diversity is essential for forensic and population studies.

Purpose of the Study:

• To sequence and characterize the short tandem repeat (STR) in the D12S391 locus.
• To determine the allelic diversity and structure of the D12S391 STR.
• To evaluate the potential utility of D12S391 as a DNA polymorphism for forensic and genetic purposes.

Main Methods:

• DNA sequencing of the D12S391 STR locus in over 40 individuals.
• Analysis of repeat number and motif variation within alleles.
• Calculation of heterozygosity and population data analysis.

Main Results:

• Twenty different alleles were identified at the D12S391 locus, classifiable into 12 allelic groups based on repeat number.
• The D12S391 STR is a compound repeat with a basic structure of (AGAT)8-17(AGAC)6-10(AGAT)0-1.
• Allele complexity varied, with larger alleles showing greater variation in tandem arrays of (AGAT) and (AGAC) motifs.
• High polymorphism was observed, with a heterozygosity exceeding 0.9.

Conclusions:

• The D12S391 STR is a highly polymorphic DNA marker with a simple yet complex structure.
• Its significant heterozygosity and structural characteristics make it a valuable tool for forensic identification and genetic research.
• Further population studies can leverage this STR for diverse genetic applications.