Contents lists available at ScienceDirect Forensic Science International: Genetics Supplement Series journal homepage: www.elsevier.com/locate/fsigss Comparison of three comercial kits to the establishment of str genetic profiles on critical samples Sara Palomo-Díez a,b, ⁎ , Cláudia Gomes a , Ángel Esparza-Arroyo b , Eduardo Arroyo-Pardo a a Forensic and Population Genetics Group, Toxicology and Health Legislation Department, Medicine School, Complutense University of Madrid, Spain b GIR PrehUSAL, Dept. of Prehistory, Ancient History and Archaeology, University of Salamanca, Spain ARTICLE INFO Keywords: STRs Critical DNA PCR ABSTRACT Nuclear DNA analysis provides great and crucial information to personal identifications and to kinship analysis. Nevertheless, nuclear DNA from human skeletal remains usually shows several problems related with its scarcity (LTD or Low Template DNA) and its modifications. Such problems compromise its analysis and results inter- pretation. For this reason, there have been developed different technics to face up to these problems, many of them based on the improvement of STR amplifying kits, for example the amplifying of miniSTRs instead of classical STRs. In the last few years, there have been developments of many of these kits, mainly those ones that concern autosomal STR amplification on critical samples. Through the present study, we would like to evaluate the efficiency of three of them (AmpFℓSTR ® MiniFiler™ PCR Amplification Kit, AmpFLSTR ® NGM™ PCR Amplification Kit, and PowerPlex ® ESX 17 System). For this purpose, there was carried out a STR analysis on 84 skeletal and/or dental samples from 42 skeletal human remains (two samples from each individual) dated back between 2000 and 5000 years of antiquity. Here we discuss the obtained results evaluating the performance of each kit. 1. Introduction The analysis of nuclear DNA is essential to solve many forensic and archaeological questions, because it provides great and crucial in- formation to personal identifications and kinship analysis [1,2]. Nevertheless, when we face up to critical samples, like human skeletal remains, the nuclear DNA analysis usually shows several problems derived from Low Template DNA (LTD) [2]. Such problems compro- mise its analysis and results interpretation, like allelic or marker dropout phenomena. For this reason, there have been developed dif- ferent technics many of them based on the improvement of STR am- plifying kits, for example the amplifying of miniSTRs instead of classical STRs, which provides shorter length markers. In the present study, we evaluate the efficiency of three autosomal STR amplification kits on critical samples: PowerPlex ® ESX 17 System PCR Kit [3] (which will be called ESX hereinafter), manufactured by Promega ® ; AmpFℓSTR ® MiniFiler™ PCR Amplification Kit [4] (from now called MiniFiler) and AmpFLSTR ® NGM™ PCR Amplification Kit [5] (called hereinafter NGM), the last two manufactured by ThermoFisher ® . Some of them have maintained the same length of the STR markers (NGM and ESX), but they have increased the number of markers included in the kit and improved the PCR efficiency [3,5]. The other strategy has been the creation of kits with shorter length markers (MiniFiler) [4]. Along this work we pretend to evaluate the efficiency of these three kits, and assess which is the best strategy to analyse autosomal STR on critical samples: creating shorter length markers or increasing the number of markers to increase the amplifying probabilities. 2. Materials and methods We have selected 84 samples (76 of them teeth) out from 42 skeletal human remains dated between 2000 and 5000 YBP (Years Before Present), selecting two samples from each individual to perform the experiment twice, according to the authenticity criteria of ancient DNA [6]. The external layer of the samples was excised with a Sand-blaster, and irradiated with UV. Subsequently, the samples were pulverized in a freezer mill filled with liquid Nitrogen. The DNA extraction was per- formed according to the protocol described by Rohland and Hofreiter [7]. DNA amplification was carried out using the three commercial kits http://dx.doi.org/10.1016/j.fsigss.2017.09.082 Received 27 August 2017; Accepted 15 September 2017 ⁎ Corresponding author at: Forensic and Population Genetics Group, Toxicology and Health Legislation Department, Medicine School, Complutense University of Madrid. Spain.Avda. Complutense s/n, 28040, Madrid, Spain. E-mail address: sarapalomodiez@med.ucm.es (S. Palomo-Díez). Forensic Science International: Genetics Supplement Series xxx (xxxx) xxx–xxx 1875-1768/ © 2017 Elsevier B.V. All rights reserved. Please cite this article as: Palomo-Díez, S., Forensic Science International: Genetics Supplement Series (2017), http://dx.doi.org/10.1016/j.fsigss.2017.09.082