Forensic Population Genetics—Short communication
Mitochondrial DNA control region variation in an autochthonous Basque population sample from the Basque Country

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Abstract

Mitochondrial control region (16024–576) sequences were generated from 106 samples from autochthonous Basques from the Autonomous Community of the Basque Country. It is especially important to generate mtDNA databases from isolated populations in order to maximize the power of discrimination of this molecular marker. It also represents a useful approach to carry out a more accurate haplogroup classification. This is the first database report of complete control region sequences in an autochthonous Basque population sample. Strict selection criteria of autochthonous individuals, automation of laboratory processing and independent reviews of the raw electropherograms ensure the high quality of these sequences and their utility as reference population data of the autochthonous Basque population.

Section snippets

Population and samples

The lack of representative mtDNA databases is one of the limitations of mitochondrial DNA, an issue that becomes more apparent in isolated populations, such as the autochthonous Basques from northern Spain. This population shows several peculiarities that have contributed to their isolation over time, such as a language, Euskera, of unknown origin which does not share an Indo-European root that characterizes the languages spoken by populations surrounding the Basque Country. Geographical

PCR amplification and sequencing

The entire control region of the mitochondrial DNA (16024–576) was amplified using primers L15988 and H616, as described in a previous study [9]. Sequences were edited and aligned using the SeqScape® Software v2.5 (Applied Biosystems, Foster City, CA), and then compared with the revised Cambridge Reference Sequence (rCRS) [10]. Sequence analysis was performed independently by two researchers as a quality control safeguard. All polymorphisms, especially point heteroplasmies and indels, were

Haplogroups classification

The mtDNA haplogroup assignment was performed according to the mtDNA tree Build 12 of the Phylotree [12].

Analysis of data

Summary statistics were calculated using the Arlequin Software v3.11 [13]. The probability of two randomly selected individuals from a population having identical mtDNA types was calculated as p=ΣXi2. The length polymorphisms of the poly-C stretches at HVS-I, HVS-II and HVS-III were disregarded in the analyses.

Access to data

All the sequences have been deposited into EMPOP under accession number EMP00365. Likewise, sequences are available online at GenBank under accession numbers HQ199898–HQ200003.

Results and discussion

Summary statistics are shown in Table 1, and haplotypes are listed in Table S1. As previously reported for the Basque people, genetic diversity of the entire control region confirms the isolate nature of this population (0.9795 ± 0.0054). Likewise, a high random match probability (0.0297) was determined. However, it is important to note that the random match probability obtained from HVS-I alone decreased from 0.0596 to 0.0297 when the entire control region was considered. Thus, even though the

Quality control

All data generated in this study are in compliance with ISFG and EDNAP guidelines for mitochondrial DNA analysis [17], [18]. This publication follows ISFG guidelines for the publication of population genetic data [6].

Conflict of interest

Authors declare no competing interest in the content of this manuscript.

Acknowledgements

This project was supported by the Government of the Basque Country (Grupo Consolidado IT-424-07). Technical and human support provided by SGIker (UPV/EHU, MICINN, GV/EJ, ESF) is gratefully acknowledged. We want to particularly acknowledge the individuals enrolled in this study for their participation and the Basque Biobank for Research-OEHUN for its collaboration. We are also grateful to the EMPOP team and especially to Prof. Walther Parson for assistance with database confirmation.

References (18)

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Cited by (0)

1

Present address: Medicina Xenómica, Dpto. de Anatomía Patolóxica e Ciencias Forenses, Universidad de Santiago de Compostela, Santiago de Compostela, Spain.

2

Present address: Dpto. Fisiología y Farmacología, Unidad de Medicina Legal, Facultad de Medicina, Universidad de Cantabria, Santander, Spain.

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