A forensic analyst routinely encounters variety of challenging samples- biological and non-biological at the crime
scene. Deoxyribose nucleic acid (DNA) extraction and its profiling are used in forensic science for establishing origin
of biological fluids found at the crime scene. In many of the biological fluids samples DNA is highly degraded. This
degraded fragmented DNA leads to poor amplification of large sized short tandem repeats (STR) loci. To get DNA
profile from these challenged forensic samples, mini-STR analysis is considered useful. In mini-STRs, primers are
located close to the repeat regions; hence shorter amplicons are generated by PCR. This improves PCR efficiency
and provides better DNA profiles.
This study reports the results of individually amplified five short tandem repeats (STRs) of Lipoprotein lipase
gene, Tyrosine hydroxylase gene, Thyroid peroxidase gene, Hypoxanthine phosphor ribosyl transferase and D5
(LPL, TH01, TPOX, HPRT and D5S818) loci as well as that of all five loci amplified together on gel. Importantstrictures
in the construction of miniplex are discussed in details. ABI 3100 Genetic Analyzer (Applied Biosystems) results for
three loci (LPL, TH01 and TPOX) are also discussed.
A meaningful DNA profile can be obtained from degraded biological samples by using mini-STRs or miniplexes.
Mini-STRs using 3 to 5 loci multiplexed together were increasingly useful in the analysis of fragmented DNA.