A practical guide to mitochondrial DNA error prevention
in clinical, forensic, and population genetics
Antonio Salas
a,
*
,A
´
ngel Carracedo
a
, Vincent Macaulay
b
, Martin Richards
c
,
Hans-Ju
¨
rgen Bandelt
d
a
Unidade de Xene
´
tica, Instituto de Medicina Legal, Facultade de Medicina, 15782 Universidade de Santiago de Compostela,
Centro Nacional de Xenotipado (CeGen), Hospital Clı
´nico
Universitario, 15706 Galicia, Spain
b
Department of Statistics, University of Glasgow, Glasgow, UK
c
School of Biology, University of Leeds, Leeds, UK
d
Fachbereich Mathematik, Universita
¨
t Hamburg, Hamburg, Germany
Received 26 July 2005
Available online 8 August 2005
Abstract
Several suggestions have been made for avoiding errors in mitochondrial DNA (mtDNA) sequencing and documentation.
Unfortunately, the current clinical, forensic, and population genetic literature on mtDNA still delivers a large number of studies
with flawed sequence data, which, in extreme cases, damage the whole message of a study. The phylogenetic approach has been
shown to be useful for pinpointing most of the errors. However, many geneticists, especially in the forensic and medical fields,
are not familiar with either effective search strategies or the evolutionary terminology. We here provide a manual that should help
prevent errors at any stage by re-examining data fresh from the sequencer in the light of previously published data. A fictitious case
study of a European mtDNA data set (albeit composed from the literature) then demonstrates the steps one has to go through in
order to assess the quality of sequencing and documentation.
Ó 2005 Elsevier Inc. All rights reserved.
Keywords: Human mtDNA; HVS-I; HVS-II; Error detection; Networks; Phylogenetic analysis; Haplogroup; SWGDAM
During the last decade, the evolution of PCR technol-
ogy, in parallel with the development of new automatic
sequencers and sequencing chemistries, has allowed the
improvement of electropherogram reliability and the
accuracy of the DNA sequence data. Large volumes of
mtDNA sequence data are nowadays produced auto-
matically and reported in the literature or in databases.
However, many errors still routinely occur, most of
which could have been avoided if careful checking strat-
egies had been applied and lab conditions critically re-
examined. A lack of knowledge in this regard seems to
persist even in population genetics and forensics, as,
for example, occasionally expressed by misrepresenta-
tion of the error issue [1,2].
Numerous papers have investigated the error issue to
date [3–9], but this effort has not yet been assimilated by
the scientific community. Most of the previous publica-
tions about errors in mitochondrial data dealt with data
sets from population genetics and forensics, but the med-
ical field seems to be most strongly affected by misse-
quencing and misdocumentation. For instance, a list of
control region mutations found in colorectal cancer pa-
tients was displayed in [10]; according to the authors, po-
sition 71 was altered in three out of seven cases (deletion
of one G). Taking into account that the majority of
mutations found to be unstable in tumors are also com-
mon polymorphisms in human populations [11],itisat
least surprising to see this highly stable site in human
0006-291X/$ - see front matter Ó 2005 Elsevier Inc. All rights reserved.
doi:10.1016/j.bbrc.2005.07.161
*
Corresponding author. Fax: +34 981 580336.
E-mail address: apimlase@usc.es (A. Salas).
www.elsevier.com/locate/ybbrc
Biochemical and Biophysical Research Communications 335 (2005) 891–899
BBRC