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Christine Keyser-Tracqui

Publications and source records attributed to Christine Keyser-Tracqui.

14 recordsLinked to original sources
PubMed2006

Population genetic data of 15 tetrameric short tandem repeats (STRs) in Berbers from Morocco.

The allele frequency distribution of 15 short tandem repeats (STR) loci contained in the AmpFlSTR Identifiler PCR Amplification Kit (Applied Biosystems), was determined in two Berber populations from Asni and Bouhria, in Central and Eastern Morocco, respectively. A total of 209 individuals were typed. No deviations from the Hardy-Weinberg equilibrium were observed for Asni at the 15 STRs loci whereas for the Bouhria samples, two loci (D5S818 and TH01) showed significant departures from Hardy-Weinberg expectations (after Bonferroni's correction). All loci are highly polymorphic and population differentiation tests showed that the Moroccan samples from Asni and Bouhria have significant differences in 4 out of 15 loci (D21S11, D7S820, D16S539 and TPOX). The aim of the study was to obtain accurate allele frequencies relevant for forensic applications. Comparative analyses between our population data and other population samples gathered from the literature are also presented.

DNA Fingerprinting↗
PubMed2006

Molecular genetic analysis of 400-year-old human remains found in two Yakut burial sites.

The excavation of five frozen graves at the Sytygane Syhe and Istekh-Myrane burial sites (dated at 400 years old) in central Yakutia revealed five human skeletons belonging to the Yakut population. To investigate the origin and evolution of the Yakut population as well as the kinship system between individuals buried in these two sites, DNA was extracted from bone samples and analyzed by autosomal short tandem repeats (STRs) and by sequencing hypervariable region I (HV1) of the mitochondrial DNA (mtDNA) control region. The results showed a diversity of sepulchral organizations linked probably to the social or genetic background of the subjects. Comparison of STR profiles, mitochondrial haplotypes, and haplogroups with data from Eurasian populations indicated affinities with Asian populations and suggested a relative specificity and continuity of part of the Yakut mitochondrial gene pool during the last five centuries. Moreover, our results did not support a Central Asian (with the exception of maternal lineage of West Eurasian origin) or Siberian origin of the maternal lineages of these ancient Yakut subjects, implying an ethnogenesis of the Yakut population probably more complex than previously proposed.

Biological Evolution↗
PubMed2006

Population origins in Mongolia: genetic structure analysis of ancient and modern DNA.

In the present study, nuclear (autosomal and Y-chromosome short tandem repeats) and mitochondrial (hypervariable region I) ancient DNA data previously obtained from a 2,300-year-old Xiongnu population of the Egyin Gol Valley (south of Lake Baikal in northern Mongolia) (Keyser-Tracqui et al. 2003 Am. J. Hum. Genet. 73:247-260) were compared with data from two contemporary Mongolian populations: one from the same location (Egyin Gol Valley plus a perimeter of less than 100 km around the valley), and one from the whole of Mongolia. The principal objective of this comparative analysis was to assess the likelihood that genetic continuity exists between ancient and present-day Mongolian populations. Since the ancient Xiongnu sample might have been composed of some of the ancestors of the present-day Yakuts, data from a present-day Yakut population, as well as published data from Turkish populations, were also included in the comparative analysis. The main result of our study was the genetic similarity observed among Mongolian samples from different periods and geographic areas. This result supports the hypothesis that the succession over time of different Turkic and Mongolian tribes in the current territory of Mongolia resulted in cultural rather than genetic exchanges. Furthermore, it appears that the Yakuts probably did not find their origin among the Xiongnu tribes, as we previously hypothesized.

Chromosomes, Human, Y↗
PubMed2006

Detection and quantification of the age-related point mutation A189G in the human mitochondrial DNA.

Mutation analysis in the mitochondrial DNA (mtDNA) control region is widely used in population genetic studies as well as in forensic medicine. Among the difficulties linked to the mtDNA analysis, one can find the detection of heteroplasmy, which can be inherited or somatic. Recently, age-related point mutation A189G was described in mtDNA and shown to accumulate with age in muscles. We carried out the detection of this 189 heteroplasmic point mutation using three technologies: automated DNA sequencing, Southern blot hybridization using a digoxigenin-labeled oligonucleotide probe, and peptide nucleic acid (PNA)/real-time PCR combined method on different biological samples. Our results give additional information on the increase in mutation frequency with age in muscle tissue and revealed that the PNA/real-time PCR is a largely more sensitive method than DNA sequencing for heteroplasmy detection. These investigations could be of interest in the detection and interpretation of mtDNA heteroplasmy in anthropological and forensic studies.

Adolescent↗
PubMed2005

STR-genotyping from human medieval tooth and bone samples.

We extracted the DNA contained in samples of bones and teeth from 10 skeletons excavated from the Gravette site (400-1000 AD, south of France). Ancient DNA was analysed by autosomal short tandem repeats (STRs). The DNA present in these ancient remains appeared very degraded, but nevertheless, better conserved in tooth than in bone samples. Moreover, we showed that the DNA extracted from ancient dental pulp was not exempt from polymerase chain reaction (PCR) inhibitors, which could result from extreme DNA fragmentation. An adapted protocol with a supplementary step of purification removed this inhibition.

Adult↗
PubMed2005

Ancient DNA analysis of human neolithic remains found in northeastern Siberia.

We successfully extracted DNA from a bone sample of a Neolithic skeleton (dated 3,600 +/- 60 years BP) excavated in northeastern Yakutia (east Siberia). Ancient DNA was analyzed by autosomal STRs (short tandem repeats) and by sequencing of the hypervariable region I (HV1) of the mitochondrial DNA (mtDNA) control region. The STR profile, the mitochondrial haplotype, and the haplogroup determined were compared with those of modern Eurasian and Native American populations. The results showed the affinity of this ancient skeleton with both east Siberian/Asian and Native American populations.

Base Sequence↗
PubMed2005

Methods for the study of ancient DNA.

Whereas the analysis of ancient DNA (aDNA) has become an increasingly popular mode of investigation in both archaeological and evolutionary studies, this approach is complicated by the degraded nature of ancient nucleic acids, the presence of enzymatic inhibitors in aDNA extracts, as well as the risk of contamination during either excavation or manipulation of samples. Despite these difficulties, numerous methods have been developed to optimize the recovery, study, and authentication of aDNA. In this article, we describe the procedures used in our laboratory to extract and amplify informative DNA segments from prehistoric or protohistoric human samples, as well as the precautions and strategies implemented to avoid or at least detect contaminations.

Archaeology↗
PubMed2005

SNPs and MALDI-TOF MS: tools for DNA typing in forensic paternity testing and anthropology.

DNA markers used for individual identification in forensic sciences are based on repeat sequences in nuclear DNA and the mitochondrial DNA hypervariable regions 1 and 2. An alternative to these markers is the use of single nucleotide polymorphisms (SNPs). These have a particular advantage in the analysis of degraded or poor samples, which are often all that is available in forensics or anthropology. In order to study the potential of SNP analysis in these fields, 41 SNPs were selected on the basis of following criteria: conservation, lack of phenotypic expression, and frequency of occurrence in populations. Thirty-six autosomal SNPs were used for genotyping 21 inclusionary and 3 exclusionary paternity cases. The behavior of 5 X-chromosome SNPs was analyzed in a French representative population. Our approach to SNP typing is a multiplex PCR based amplification followed by simultaneous detection by primer extension (PEX) analyzed by Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS). The selected autosomal SNPs showed independent inheritance and gave clear results in paternity investigation. All X-SNPs were useful as both paternity and identification markers. PEX and MALDI-TOF MS, with their high sensitivity, precision and speed, gave a powerful method for forensic and anthropological exploitation of biallelic markers.

Chromosomes, Human, X↗
PubMed2004

The EDNAP mitochondrial DNA population database (EMPOP) collaborative exercises: organisation, results and perspectives.

This paper presents an overview of the organisation and the results of the collaborative exercises (CE) of the European DNA Profiling (EDNAP) Group's mitochondrial DNA population database project (EMPOP). The aim of the collaborative exercises was to determine whether uniformity of mtDNA sequencing results could be achieved among different laboratories. These were asked to sequence either the complete mtDNA control region or the two hypervariable regions HVI (16024-16365) and HVII (73-340) from DNA extracts, buccal swabs or bloodstains, proceeding in accordance with the protocol and strategies used in each individual laboratory. The results of the collaborative exercises were employed to identify possible sources of errors that could arise during the analysis and interpretation of mtDNA profiles. These findings were taken as a basis to tentatively make suitable arrangements for the construction of a high quality mtDNA database. One hundred fifty mtDNA profiles were submitted to the evaluating laboratory, and disaccording profiles were classified into four groups corresponding to the source of error: clerical errors, sample mix-ups, contaminations and discrepancies with respect to the mtDNA nomenclature. Overall, 14 disaccording haplotypes (16 individual errors) were observed. The errors included 10 clerical errors, 3 interpretation problems, 2 cases of sample mix-up and 1 case of point heteroplasmic mixture, where the 2 sequencing reactions brought inconsistent base calls. This corresponds to an error rate of 10.7% in a virtual mtDNA database consisting of the collaborative exercise results. However, this estimate is still conservative compared to conclusions drawn by authors of meanwhile numerous publications critically reviewing published mtDNA population databases. Our results and earlier published concerns strongly emphasize the need for appropriate safety regulations when mtDNA profiles are compiled for database purposes in order to accomplish the high standard required for mtDNA databases that are used in the forensic context.

Clinical Laboratory Techniques↗
PubMed2004

Genetic analysis and ethnic affinities from two Scytho-Siberian skeletons.

We extracted DNA from two skeletons belonging to the Sytho-Siberian population, which were excavated from the Sebÿstei site (dating back 2,500 years) in the Altai Republic (Central Asia). Ancient DNA was analyzed by autosomal short tandem repeats (STRs) and by the sequencing of the hypervariable region 1 (HV1) of the mitochondrial DNA (mtDNA) control region. The results showed that these two skeletons were not close relatives. Moreover, their haplogroups were characteristic of Asian populations. Comparison with the haplogroup of 3,523 Asian and American individuals linked one skeleton with a putative ancestral paleo-Asiatic population and the other with Chinese populations. It appears that the genetic study of ancient populations of Central Asia brings important elements to the understanding of human population movements in Asia.

Adult↗
PubMed2003

Genetic analysis of human remains found in two eighteenth century Yakut graves at At-Dabaan.

We extracted DNA from three skeletons belonging to the Yakut population, which were excavated from the At-Dabaan site (dating back 300 years) in the Sakha Republic (Russia). Ancient DNA was analyzed by autosomal STRs (short tandem repeats) and by the sequencing of the hypervariable region 1 (HV1) of the mitochondrial DNA (mtDNA) control region. The results showed that these three skeletons were not close relatives but probably linked to the same clan structure. Comparison of their haplotypes with the haplotypes of 8,774 Eurasian individuals suggested a relative specificity and continuity of part of the Yakut mitochondrial gene pool during the last 3 centuries.

Anthropology, Physical↗
PubMed2003

Nuclear and mitochondrial DNA analysis of a 2,000-year-old necropolis in the Egyin Gol Valley of Mongolia.

DNA was extracted from the skeletal remains of 62 specimens excavated from the Egyin Gol necropolis, in northern Mongolia. This burial site is linked to the Xiongnu period and was used from the 3rd century b.c. to the 2nd century a.d. Three types of genetic markers were used to determine the genetic relationships between individuals buried in the Egyin Gol necropolis. Results from analyses of autosomal and Y chromosome short tandem repeats, as well as mitochondrial DNA, showed close relationships between several specimens and provided additional background information on the social organization within the necropolis as well as the funeral practices of the Xiongnu people. To the best of our knowledge, this is the first study using biparental, paternal, and maternal genetic systems to reconstruct partial genealogies in a protohistoric necropolis.

Alleles↗
PubMed2003

[Y-chromosome analysis].

After initially slow progress in identifying DNA polymorphisms on the non recombining part of the human Y chromosome, a large number of polymorphic markers are now available to define individual or population-specific haplotypes or haplogroups. Among them the Y-chromosomal STRs (Short Tandem Repeats) have been increasingly used over the past few years for the study of human evolution as well as for human identification in forensic case-work and paternity testing. After a brief summary of the features of such markers, this paper deals with some applications of the Y-STR haplotyping.

Chromosomes, Human, Y↗