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Las Palmas de Gran Canaria, Spain

Secher B.,Administrator of U6 MtDNA Project at Family Tree DNA | Fregel R.,University of La Laguna | Fregel R.,University of Las Palmas de Gran Canaria | Larruga J.M.,University of La Laguna | And 5 more authors.
BMC Evolutionary Biology | Year: 2014

Background: Complete mitochondrial DNA (mtDNA) genome analyses have greatly improved the phylogeny and phylogeography of human mtDNA. Human mitochondrial DNA haplogroup U6 has been considered as a molecular signal of a Paleolithic return to North Africa of modern humans from southwestern Asia. Results: Using 230 complete sequences we have refined the U6 phylogeny, and improved the phylogeographic information by the analysis of 761 partial sequences. This approach provides chronological limits for its arrival to Africa, followed by its spreads there according to climatic fluctuations, and its secondary prehistoric and historic migrations out of Africa colonizing Europe, the Canary Islands and the American Continent. Conclusions: The U6 expansions and contractions inside Africa faithfully reflect the climatic fluctuations that occurred in this Continent affecting also the Canary Islands. Mediterranean contacts drove these lineages to Europe, at least since the Neolithic. In turn, the European colonization brought different U6 lineages throughout the American Continent leaving the specific sign of the colonizers origin. © 2014 Secher et al.; licensee BioMed Central Ltd. Source


Fregel R.,University of La Laguna | Fregel R.,Institute of Legal Medicine of Las Palmas | Delgado S.,University of La Laguna
Mitochondrion | Year: 2011

Comparison of available mitochondrial DNA data is some times hindered by the data presentation format. HaploSearch is a simple tool for transforming DNA sequences into haplotype data and vice versa, speeding up the manipulation of large datasets. Although designed for mitochondrial DNA, HaploSearch could be used with any kind of DNA type. HaploSearch program, detailed software instructions and example files are freely available on the web http://www.haplosite.com/haplosearch/. © 2010 Elsevier B.V. and Mitochondria Research Society. Source


Almeida M.,Institute of Legal Medicine of Las Palmas | Betancor E.,Institute of Legal Medicine of Las Palmas | Fregel R.,Institute of Legal Medicine of Las Palmas | Suarez N.M.,University of Las Palmas de Gran Canaria | And 2 more authors.
Forensic Science International: Genetics Supplement Series | Year: 2011

Hairs are common biological samples in crime scene investigation. However, most of this evidence is comprised of hair fragments without the root. As the major part of DNA is located in the root, hair shafts are usually problematic samples in forensic analysis. For these reasons, hair DNA typing is directed at mitochondrial DNA (mtDNA), which is present in high copy number in each cell, instead of nuclear DNA analysis. In our laboratory, we have used the PrepFiler BTA™ extraction method for routinely processing difficult samples such as old bones or cigarette butts, obtaining good quality DNA in all cases. As the use of automatic extraction methods has been progressively introduced in forensic laboratories, we have tested the applicability of the PrepFiler BTA™ extraction method in combination with AutoMate Express™ equipment, to the analysis of hair shafts. In order to determine the efficiency of the method, DNA extractions were quantified using a real-time PCR approach, and mtDNA fragments of different lengths were amplified to determine DNA degradation. We also processed several types of hairs, with different characteristics (thickness, gender, antiquity and hair dyeing) and from diverse ethnical groups. In all cases, the PrepFiler BTA Express™ extraction method showed very reproducible results in obtaining DNA from hair shafts, its application being highly recommendable as a routine protocol in forensic laboratories. © 2011 Elsevier Ireland Ltd. Source


Fregel R.,Institute of Legal Medicine of Las Palmas | Almeida M.,Institute of Legal Medicine of Las Palmas | Betancor E.,Institute of Legal Medicine of Las Palmas | Suarez N.M.,University of Las Palmas de Gran Canaria | And 2 more authors.
Forensic Science International: Genetics Supplement Series | Year: 2011

DNA quantification is a prerequisite for both low copy number (LCN) forensic analysis and ancient DNA (aDNA) studies. Moreover, if nuclear quantification is focused on the amelogenin locus, it also allows sex determination. Some of the problems of these techniques are allelic drop-out phenomenon in amelogenin locus and mitochondrial DNA (mtDNA) quantification biases, due to human intraspecific variation affecting the annealing of primers and/or probes. The method presented here combines two multiplex TaqMan® real-time PCR (qPCR) for nuclear and mtDNA quantification in degraded or limited samples. Nuclear DNA detection is based on the independent amplification of X and Y chromosome specific fragments in the amelogenin locus and an internal PCR control (IPC) to recognize inhibition problems. The small length of the fragments (71bp) favors the quantification of severely degraded DNA, whereas the use of two distinct primer sets for X and Y chromosome amplification is directed to reduce allelic drop-out in LCN analysis. MtDNA quantification is based on the amplification of three PCR fragments located in the mtDNA 16S region. Two of them are amplified with human specific conservative primers and probes, which allows a world-wide application of this technique. Moreover, their length difference (167 and 314bp respectively), provides information about the DNA degradation level. In order to also recognize non-human DNA an interspecific mtDNA fragment (187bp) was also designed. © 2011 Elsevier Ireland Ltd. Source


Betancor E.,Institute of Legal Medicine of Las Palmas | Fregel R.,Institute of Legal Medicine of Las Palmas | Almeida M.,Institute of Legal Medicine of Las Palmas | Suarez N.M.,University of Las Palmas de Gran Canaria | And 2 more authors.
Forensic Science International: Genetics Supplement Series | Year: 2011

During the Spanish Civil War (1936-1939), the Canary Islands suffered one of the highest levels of repression by the insurgent side, even though there were no battles in the islands. More than 50 people were killed in the island of La Palma between July 1936 and June 1937. The Association for the Recovery of Historical Memory in La Palma, made up of relatives of people who went missing during the Civil War, located the Fuencaliente mass graves in 2004. The excavation process recovered eight skeletal remains. The aim of this work was the genetic identification of these reprisal victims. In general, obtaining nuclear DNA profiles from old skeletal samples is known to be difficult. Due to the age and conservation conditions, this was the case for the Fuencaliente remains. For these reasons, we firstly attempted to analyze the mitochondrial DNA (mtDNA). Although mtDNA control region sequences were obtained for the eight skeletal remains, the limited number of possible maternal relative donors complicated identification based only on mtDNA. Taking into account the problems in establishing identity by using mtDNA, a few years later we were presented with the possibility of analyzing nuclear DNA using the new PrepFiler Express BTA™ Forensic DNA extraction methodology. This extraction protocol, in combination with the new AmpFℓSTR® NGM™ PCR Amplification Kit (Applied Biosystems), allowed us to obtain full nuclear DNA profiles for the eight victims. In conclusion, the use of specific protocols designed for old DNA samples, such as PrepFiler Express BTA™ Forensic DNA extraction and AmpFℓSTR® NGM™ PCR amplification kit seems to be crucial for obtaining full nuclear profiles that allow statistically significant identification of the putative relatives. © 2011 Elsevier Ireland Ltd. Source

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