Tanya Chauhan (2015) Identiication of Variant alleles at CODIS STR loci in Different Populations of India. Int J Forensic Sci Pathol. 3(9), 172-175 172 http://scidoc.org/IJFP.php International Journal of Forensic Science & Pathology (IJFP) ISSN 2332-287X Identiication of Variant Alleles at CODIS STR loci in Different Populations of India Research Article Tanya Chauhan LNJN National Institute of Criminology and Forensic Science, Sector-3, Rohini, Delhi, India. *Corresponding Author: Tanya Chauhan, LNJN National Institute of Criminology and Forensic Science, Sector-3, Rohini, Delhi, India. E-mail: tanyachauhan@yahoo.com Received: July 08, 2015 Accepted: September 10, 2015 Published: September 12, 2015 Citation: Tanya Chauhan (2015) Identiication of Variant alleles at CO- DIS STR loci in Different Populations of India. Int J Forensic Sci Pathol. 3(9), 172-175. doi: http://dx.doi.org/10.19070/2332-287X-1500042 Copyright: Tanya Chauhan © 2015. This is an open-access article dis- tributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any me- dium, provided the original author and source are credited. Introduction Polymorphic Short Tandem Repeat (STR) loci have become use- ful tool for DNA analysis and typing for human identiication and paternity testing for forensic purposes in most of the forensic laboratories in the world [1, 2]. STR alleles of a questioned indi- vidual are designated by comparing with alleles of allelic ladder, provided by manufacturer of commercial kit [3]. Allelic ladder is the combination of alleles based on population genetic variations observed in developmental process. STR alleles of most of the DNA proiles represented with in allelic ladder are found in a small number of individuals. For proper casework interpretations, the forensic scientists should be aware of the existence of rare alleles so that the variants can be recognised. Correctly designated alleles can sometimes greatly in- creased power of discrimination of STR analysis. It is, therefore, important that forensic scientists should share information on the occurrence of these variants in different populations. India is culturally and geographically a highly diverse country. Hu- man Diversity in India is deined by 4693 different documented population groups that include 2205 major communities, 589 segments and 1900 territorial units spread across the country [4]. This diversity is due to different cultural heritage (linguistic, ethnic etc.), history of different waves of migration and impact of deep seated caste systems (or practice of strict endogamy/marriage rule). In this study, 3 variant alleles were found at 3 GenePrint STR loci, viz. TPOX, TH01 and vWA (Promega Corporation, Madison, US) during Indian population studies. Materials and Methods Samples and DNA extraction A total of 244 blood samples were collected from unrelated in- dividuals of two populations namely Rajputs and Ramgaria-Sikhs from Delhi, India. Genomic DNA from each sample was extract- ed by Phenol: Chloroform extraction method [5]. Whole blood sample was used as a DNA source. Extracted DNA samples were quantiied by using NanoDrop spectrophotometer. PCR Ampliication and STR typing About 2-5 ng of total DNA was used as template DNA in a total reaction volume of 25 µl for each ampliication process. Initial- ly, 244 samples were screened for 12 STR loci namely CSF1PO, D16S539, D7S820, D13S317, F13A01, F13B, FESFPS, HPRTB, LPL, TPOX, TH01 and vWA using GenePrint STR system (Pro- mega Corporation, Madison, US) and polyacrylamide gel electro- phoresis. Thermal cycling parameters were setup according to the manu- facturer’s protocol (Promega Corporation, Madison, US). Ampli- ication products (2.5 µl per sample mixed with an equal volume of STR 2X loading solution) were electrophoresed at 50 Watt for 2-4 h on a 40cmX20cm, 0.35mm thick 6% denaturing polyacryla- mide gel by manual GenoSequencer (Atto Corporation, Japan) with 0.5X TBE as gel running buffer. The bands were visualized by staining with silver stain [6]. Direct comparison between the al- Abstract Two population’s DNA proiling was screened for variant alleles not included within the allelic ladder provided by the manufacturer of GenePrint STR system (Promega Corporation, Madison, US). A total of 3 variant alleles were identiied at 3 out of 12 STR loci tested. This study identiied one variant allele at TH01 locus (allele 8.3), one at TPOX locus (allele 14) and one at vWA locus (allele 21). All these alleles have been reported previously in different populations. Allele 8.3 found at TH01 fell within the allelic range while allele 14 found at TPOX and allele 21 found at vWA fell outside the allelic range. Keywords: Variant Alleles; CODIS STR; Forensics; TPOX; TH01; vWA.