Molecular Characterization and Genetic Significance of a Rare Type-I Triallelic Pattern Involving a 15.3 Microvariant...

Area of Science:

• Forensic Genetics
• Molecular Biology
• Human Genetics

Background:

• Short tandem repeat (STR) analysis is a cornerstone of forensic genetics.
• Rare genetic anomalies, such as triallelic patterns and microvariants, can complicate STR profile interpretation.
• Accurate interpretation relies on comprehensive understanding of genetic variations.

Purpose of the Study:

• To characterize an exceptional triallelic pattern identified during routine forensic casework.
• To document a novel short tandem repeat (STR) variation for forensic databases.
• To investigate the genetic basis of the observed triallelic pattern.

Main Methods:

• DNA isolation from dental remains of an unidentified male.
• Autosomal STR loci amplification using the Investigator® ESSplex SE Plus kit.
• Quantitative peak height analysis and comparison with global STR databases.

Main Results:

• A triallelic pattern was identified at the D19S433 locus, featuring alleles 13, 14, and a microvariant designated 15.3.
• Quantitative analysis indicated a Type I triallelic configuration, suggesting somatic mutation or segmental duplication.
• The specific 13/14/15.3 allele combination was not previously documented in global or regional databases.

Conclusions:

• The documentation of rare STR variations, like the one found at D19S433, is crucial for enhancing forensic genomic databases.
• This finding contributes to the accuracy and reliability of forensic DNA profile interpretation.
• Understanding such anomalies is vital for robust identification processes in forensic science.