Publications by authors named "Josefina Gómez"

4 Publications

  • Page 1 of 1

Mitochondrial DNA error prophylaxis: assessing the causes of errors in the GEP'02-03 proficiency testing trial.

Forensic Sci Int 2005 Mar;148(2-3):191-8

Unidad de Genética, Facultad de Medicina de la Universidad de Santiago de Compostela, Instituto de Medicina Legal, A Coruña, Galicia-Spain.

We report the results of the Spanish and Portuguese working group (GEP) of the International Society for Forensic Genetics (ISFG) Collaborative Exercise 2002-2003 on mitochondrial DNA (mtDNA) analysis. Six different samples were submitted to the participating laboratories: four blood stains (M1-M2-M3-M4), one mixture blood sample (M5), and two hair shaft fragments (M6). Most of the labs reported consensus results for the blood stains, slightly improving the results of previous collaborative exercises. Although hair shaft analysis is still carried out by a small number of laboratories, this analysis yielded a high rate of success. On the contrary, the analysis of the mixture blood stain (M5) yielded a lower rate of success; in spite of this, the whole results on M5 typing demonstrated the suitability of mtDNA analysis in mixture samples. We have found that edition errors are among the most common mistakes reported by the different labs. In addition, we have detected contamination events as well as other minor problems, i.e. lack of standarization in nomenclature for punctual and length heteroplasmies, and indels. In the present edition of the GEP-ISFG exercise we have paid special attention to the visual phylogenetic inspection for detecting common sequencing errors.
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http://dx.doi.org/10.1016/j.forsciint.2004.06.008DOI Listing
March 2005

The 2000-2001 GEP-ISFG Collaborative Exercise on mtDNA: assessing the cause of unsuccessful mtDNA PCR amplification of hair shaft samples.

Forensic Sci Int 2003 Jun;134(1):46-53

Comisara General de Policía Científica, Sección de Biología-ADN, Madrid, Spain.

We report the results of Spanish and Portuguese working group (GEP) of International Society of Forensic Genetics (ISFG) Collaborative Exercise 2001-2002 on mitochondrial DNA (mtDNA) analysis. 64 laboratories from Spain, Portugal and several Latin-American countries participated in this quality control exercise. Five samples were sent to the participating laboratories, four blood stains (M1-M4) and a sample (M5) consisting of two hair shaft fragments. M4 was non-human (Felis catus) in origin; therefore, the capacity of the labs to identify the biological source of this sample was an integral part of the exercise. Some labs detected the non-human origin of M4 by carrying out immuno-diffussion techniques using antihuman serum, whereas others identified the specific animal origin by testing the sample against a set of animal antibodies or by means of the analysis of mtDNA regions (Cyt-b, 12S, and 16S genes). The results of the other three human blood stains (M1-M3) improved in relation to the last Collaborative Exercises but those related to hairs yielded a low rate of success which clearly contrasts with previous results. As a consequence of this, some labs performed additional analysis showing that the origin of this low efficiency was not the presence of inhibitors, but the low quantity of DNA present in these specific hair samples and the degradation. As a general conclusion the results emphasize the need of external proficiency testing as part of the accreditation procedure for the labs performing mtDNA analysis in forensic casework.
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http://dx.doi.org/10.1016/s0379-0738(03)00095-1DOI Listing
June 2003

Alcohol, illicit drugs and medicinal drugs in fatally injured drivers in Spain between 1991 and 2000.

Forensic Sci Int 2002 Jun;127(1-2):63-70

Drugs and Alcohol Research Group, Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Valladolid, Spain.

The aim of this study was to assess the presence of alcohol, illicit drugs and medicinal drugs among Spanish drivers involved in fatal road accidents between 1991 and 2000. Samples were obtained for 5745 drivers killed in road accidents from January 1991 to December 2000. Of the samples, 91.7% represented males and 8.3% females; 40.7% were under 30 years of age, 31.9% were under 31-50 years of age, 19.5% were over 51 years of age, and for 7.9% the age was unknown. Between 1991 and 2000, some type of psychoactive substance was detected among 50.1% of those drivers killed in road accidents, this being mainly alcohol (43.8%) and, less frequently, illicit drugs (8.8%) and medicinal drugs (4.7%). In all the cases, in which alcohol was detected, combined use with other substances accounted for only 12.5%, whilst in the case of illicit and medicinal drugs, figures representing combined use with other substances were 75.6% for the former and 65.8% for the latter. For one in every three cases (32.0%), a blood alcohol level over 0.8 g/l was recorded; cocaine (5.2%), opiates (3.2%) and cannabis (2.2%) were the three illicit drugs most frequently detected. Among medicinal drugs, were benzodiazepines (3.4%), anti-depressant drugs (0.6%) and analgesics (0.4%). The results show the frequent presence of psychoactive substances, particularly alcohol, among Spanish motor vehicle users involved in fatal road accidents. It should be pointed out that illicit and medicinal drugs in combination with other substances were a common feature.
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http://dx.doi.org/10.1016/s0379-0738(02)00116-0DOI Listing
June 2002

Results of the 1999-2000 collaborative exercise and proficiency testing program on mitochondrial DNA of the GEP-ISFG: an inter-laboratory study of the observed variability in the heteroplasmy level of hair from the same donor.

Forensic Sci Int 2002 Jan;125(1):1-7

Departamento de Madrid, Instituto de Toxicología, Sección de Biología, Luis Cabrera 9, 28002 Madrid, Spain.

The Spanish and Portuguese working group (GEP) of international society for forensic genetics (ISFG) 1999-2000 collaborative exercise on mitochondrial DNA (mtDNA) included the analysis of four bloodstain samples and one hair shaft sample by 19 participating laboratories from Spain, Portugal and several Latin-American countries. A wide range of sequence results at position 16,093 of the HV1 (from T or C homoplasmy to different levels of heteroplasmy) were submitted by the different participating laboratories from the hair shaft sample during the first phase of this exercise. During the discussion of these results in the Annual GEP-ISFG 2000 Conference a second phase of this exercise was established with two main objectives: (i) to evaluate the incidence of the HV1 sequence heteroplasmy detected in Phase I across different sample types from the same donor including blood, saliva, and hair shafts, (ii) to perform a technical review of the electropherograms to evaluate the relative levels of heteroplasmies obtained by the different laboratories and also to examine the source of possible errors detected in Phase I. Anonymous review of the raw sequence data permitted the detection of three transcription errors and three errors due to methodological problems. Highly variable levels of heteroplasmy were found in the hair shaft and more stability in blood and saliva. Three laboratories found variable levels of heteroplasmy at position 16,093 across adjacent fragments from the same hair shaft. Two laboratories also described more than one heteroplasmic position from a single hair. The relevance of these findings for the interpretation of mtDNA data in the forensic context is also discussed.
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http://dx.doi.org/10.1016/s0379-0738(01)00602-8DOI Listing
January 2002