Las Palmas de Gran Canaria, Spain
Las Palmas de Gran Canaria, Spain

Time filter

Source Type

Fregel R.,University of Las Palmas de Gran Canaria | Fregel R.,University of La Laguna | Fregel R.,Stanford University | Seetah K.,Stanford University | And 8 more authors.
PLoS ONE | Year: 2014

This article reports on the first genetic assessment of the contemporary Mauritian population. Small island nodes such as Mauritius played a critical role in historic globalization processes and revealing high-resolution details of labour sourcing is crucial in order to better understand early-modern diaspora events. Mauritius is a particularly interesting case given detailed historic accounts attesting to European (Dutch, French and British), African and Asian points of origin. Ninety-seven samples were analysed for mitochondrial DNA to begin unravelling the complex dynamics of the island's modern population. In corroboration with general demographic information, the majority of maternal lineages were derived from South Asia (58.76%), with Malagasy (16.60%), East/Southeast Asian (11.34%) and Sub-Saharan African (10.21%) also making significant contributions. This study pinpoints specific regional origins for the South Asian genetic contribution, showing a greater influence on the contemporary population from northern and southeast India. Moreover, the analysis of lineages related to the slave trade demonstrated that Madagascar and East Asia were the main centres of origin, with less influence from West Africa. © 2014 Fregel et al.


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.


Bekada A.,Oran University of Science and Technology - Mohamed Boudiaf | Fregel R.,University of La Laguna | Fregel R.,University of Las Palmas de Gran Canaria | Fregel R.,Institute of Legal Medicine of Las Palmas | And 6 more authors.
PLoS ONE | Year: 2013

North Africa is considered a distinct geographic and ethnic entity within Africa. Although modern humans originated in this Continent, studies of mitochondrial DNA (mtDNA) and Y-chromosome genealogical markers provide evidence that the North African gene pool has been shaped by the back-migration of several Eurasian lineages in Paleolithic and Neolithic times. More recent influences from sub-Saharan Africa and Mediterranean Europe are also evident. The presence of East-West and North-South haplogroup frequency gradients strongly reinforces the genetic complexity of this region. However, this genetic scenario is beset with a notable gap, which is the lack of consistent information for Algeria, the largest country in the Maghreb. To fill this gap, we analyzed a sample of 240 unrelated subjects from a northwest Algeria cosmopolitan population using mtDNA sequences and Y-chromosome biallelic polymorphisms, focusing on the fine dissection of haplogroups E and R, which are the most prevalent in North Africa and Europe respectively. The Eurasian component in Algeria reached 80% for mtDNA and 90% for Y-chromosome. However, within them, the North African genetic component for mtDNA (U6 and M1; 20%) is significantly smaller than the paternal (E-M81 and E-V65; 70%). The unexpected presence of the European-derived Y-chromosome lineages R-M412, R-S116, R-U152 and R-M529 in Algeria and the rest of the Maghreb could be the counterparts of the mtDNA H1, H3 and V subgroups, pointing to direct maritime contacts between the European and North African sides of the western Mediterranean. Female influx of sub-Saharan Africans into Algeria (20%) is also significantly greater than the male (10%). In spite of these sexual asymmetries, the Algerian uniparental profiles faithfully correlate between each other and with the geography. © 2013 Bekada et al.


Suarez N.M.,University of Las Palmas de Gran Canaria | Suarez N.M.,Nationwide Childrens Hospital | Betancor E.,Institute of Legal Medicine of Las Palmas | Fregel R.,University of Las Palmas de Gran Canaria | And 2 more authors.
Animal Genetics | Year: 2013

Many studies presenting genetic analysis of dog breeds have been conducted without the inclusion of island dog breeds, although isolation can be one of the main factors in their origin. Here we report the genetic analysis at the nuclear and mitochondrial DNA levels of five Canary Island dog breeds (Canarian Warren Hound, Canary Island Mastiff, Garafiano Shepherd, La Palma Rat-Hunter and El Hierro Wolfhound) to fill this gap and, at the same time, genetically characterize these breeds. We identified 168 alleles in autosomal microsatellites and 16 mitochondrial haplotypes. Observed and expected heterozygosities ranged from 0.556 to 0.783 and from 0.737 to 0.943 respectively. Furthermore, three haplotypes were newly described and exclusive to a particular breed (A17+ in the Canary Island Mastiff; A33+ in the Canarian Warren Hound; Bi in the La Palma Rat-Hunter). The outcome of our analyses also revealed different breed histories consistent with historical documents and hypothetical origin designations. Although mtDNA haplotypes showed poor breed discriminating power, autosomal markers allowed a clear clustering of each single population. We expect that our results, together with further analyses, will help to make the population histories of island dog breeds clearer. © 2013 The Authors, Animal Genetics © 2013 Stichting International Foundation for Animal Genetics.


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.


Fregel R.,University of Las Palmas de Gran Canaria | Fregel R.,University of La Laguna | Suarez N.M.,University of Las Palmas de Gran Canaria | Betancor E.,Institute of Legal Medicine of Las Palmas | And 4 more authors.
Mitochondrion | Year: 2015

Canis lupus familiaris mitochondrial DNA analysis has increased in recent years, not only for the purpose of deciphering dog domestication but also for forensic genetic studies or breed characterization. The resultant accumulation of data has increased the need for a normalized and phylogenetic-based nomenclature like those provided for human maternal lineages. Although a standardized classification has been proposed, haplotype names within clades have been assigned gradually without considering the evolutionary history of dog mtDNA. Moreover, this classification is based only on the D-loop region, proven to be insufficient for phylogenetic purposes due to its high number of recurrent mutations and the lack of relevant information present in the coding region.In this study, we design 1) a refined mtDNA cladistic nomenclature from a phylogenetic tree based on complete sequences, classifying dog maternal lineages into haplogroups defined by specific diagnostic mutations, and 2) a coding region SNP analysis that allows a more accurate classification into haplogroups when combined with D-loop sequencing, thus improving the phylogenetic information obtained in dog mitochondrial DNA studies. © 2015 Elsevier B.V.


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.


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.


PubMed | University of Las Palmas de Gran Canaria and Institute of Legal Medicine of Las Palmas
Type: Journal Article | Journal: Science & justice : journal of the Forensic Science Society | Year: 2015

Pesticides are frequently responsible for human poisoning and often the information on the involved substance is lacking. The great variety of pesticides that could be responsible for intoxication makes necessary the development of powerful and versatile analytical methodologies, which allows the identification of the unknown toxic substance. Here we developed a methodology for simultaneous identification and quantification in human blood of 109 highly toxic pesticides. The application of this analytical scheme would help in minimizing the cost of this type of chemical identification, maximizing the chances of identifying the pesticide involved. In the methodology that we present here, we use a liquid-liquid extraction, followed by one single purification step, and quantitation of analytes by a combination of liquid and gas chromatography, both coupled to triple quadrupole mass spectrometry, which is operated in the mode of multiple reaction monitoring. The methodology has been fully validated, and its applicability has been demonstrated in two recent cases involving one self-poisoning fatality and one non-fatal homicidal attempt.


PubMed | University of La Laguna, University of Las Palmas de Gran Canaria and Institute of Legal Medicine of Las Palmas
Type: | Journal: Mitochondrion | Year: 2015

Canis lupus familiaris mitochondrial DNA analysis has increased in recent years, not only for the purpose of deciphering dog domestication but also for forensic genetic studies or breed characterization. The resultant accumulation of data has increased the need for a normalized and phylogenetic-based nomenclature like those provided for human maternal lineages. Although a standardized classification has been proposed, haplotype names within clades have been assigned gradually without considering the evolutionary history of dog mtDNA. Moreover, this classification is based only on the D-loop region, proven to be insufficient for phylogenetic purposes due to its high number of recurrent mutations and the lack of relevant information present in the coding region. In this study, we design 1) a refined mtDNA cladistic nomenclature from a phylogenetic tree based on complete sequences, classifying dog maternal lineages into haplogroups defined by specific diagnostic mutations, and 2) a coding region SNP analysis that allows a more accurate classification into haplogroups when combined with D-loop sequencing, thus improving the phylogenetic information obtained in dog mitochondrial DNA studies.

Loading Institute of Legal Medicine of Las Palmas collaborators
Loading Institute of Legal Medicine of Las Palmas collaborators