Biomedical subjects

Niels Lynnerup

Publications and source records attributed to Niels Lynnerup.

15 recordsLinked to original sources

PubMed2006

The last Viking King: a royal maternity case solved by ancient DNA analysis.

The last of the Danish Viking Kings, Sven Estridsen, died in a.d. 1074 and is entombed in Roskilde Cathedral with other Danish kings and queens. Sven's mother, Estrid, is entombed in a pillar across the chancel. However, while there is no reasonable doubt about the identity of Sven, there have been doubts among historians whether the woman entombed was indeed Estrid. To shed light on this problem, we have extracted and analysed mitochondrial DNA (mtDNA) from pulp of teeth from each of the two royals. Four overlapping DNA-fragments covering about 400bp of hypervariable region 1 (HVR-1) of the D-loop were PCR amplified, cloned and a number of clones with each segment were sequenced. Also a segment containing the H/non-H specific nucleotide 7028 was sequenced. Consensus sequences were determined and D-loop results were replicated in an independent laboratory. This allowed the assignment of King Sven Estridsen to haplogroup H; Estrid's sequence differed from that of Sven at two positions in HVR-1, 16093T-->C and 16304T-->C, indicating that she belongs to subgroup H5a. Given the maternal inheritance of mtDNA, offspring will have the same mtDNA sequence as their mother with the exception of rare cases where the sequence has been altered by a germ line mutation. Therefore, the observation of two sequence differences makes it highly unlikely that the entombed woman was the mother of Sven. In addition, physical examination of the skeleton and the teeth strongly indicated that this woman was much younger (approximately 35 years) at the time of death than the 70 years history records tell. Although the entombed woman cannot be the Estrid, she may well be one of Sven's two daughters-in-law who were also called Estrid and who both became queens.

Base Sequence↗

PubMed2006

Evaluation of post-mortem estimated dental age versus real age: a retrospective 21-year survey.

The aim of the study was to evaluate the reliability of methods used for forensic dental age estimation. We analysed all cases over the last 21 years (1984-2004) of unidentified bodies that were examined for identification purposes (including age assessment), and of which secure identification was subsequently achieved. In total, the study included 51 cases and 7 different methods had been used for dental age estimation, with the Bang/Ramm and the Gustafson/Johanson methods being the most frequently applied. The age estimates had usually been recorded as 10-year intervals. Factual ages at death were in the range of 6-76 years, with the largest concentration of cases being in the age interval of 25-55 years (34 cases). There was good agreement between estimated age interval and factual age at death in 37/51 (72%) of the cases. In eight cases the factual age at death deviated up to +/-5 years from the estimated age, and in six cases by more than 6 years. The average difference between factual age at death and estimated age was 4.5 years. The four subadults in the material were all correctly estimated within an age range of +/-3 years. Our study showed that forensic odontological age estimates are reliable. However, the implementation of the specific methods may need to be adjusted concerning age ranges. In the future we recommend to register anamnestic information and the different steps in the methods used. Clinical evaluation should contain more details about attrition, colour, number and presumed age of the restorations and periodontal status.

Adolescent↗

PubMed2006

Assessment of age at death by microscopy: unbiased quantification of secondary osteons in femoral cross sections.

The microscopic method of age at death determination was introduced by Kerley in 1965 [E.R. Kerley, The microscopic determination of age in human bone, Am. J. Phys. Anthropol, 23 (1965) 149-163.]. However, even though the method has been revised several times, there remain some fundamental issues concerning the reliability of the methods. This is because several basic histological features seen in a cross section of a bone have to be quantified according to the method, but the definition, and hence quantification, of these features leaves room for subjectivity. In a previous study we found that some of these features (osteon fragments and Haversian canals) could not be identified reliably. Only secondary osteons could be identified with a low inter and intra observer error. Furthermore, since the histological features are quantified in only parts of an entire bone cross section, the selection of these parts or areas is a potential source of bias. Finally, unless an unbiased method is used for addressing features on the borders of the selected areas, this will also introduce error. These issues have not been addressed specifically in previous studies. In this study, we used the methods of stereology to choose the regions of interest, as well as for dealing with border phenomena, and we only counted secondary osteons. Our results show a statistically significant increase in the median number of osteons per area unit with increasing age at death. However, this was after exclusion of one outlier. This result is probably due to the limited sample size (N = 24). As such, this study is preliminary, but does warrant applying the described techniques to a larger sample.

Adolescent↗

PubMed2006

Comparison of handmarks in manual strangulation: an experimental study.

A police case with a strangulated woman with fingermarks on the neck and two suspects identifying each other as the perpetrator set off a laboratory experiment. Twenty-one males participated in the study. Blue paint was applied to their fingers, after which they grasped a neck dummy and pressed hard as if strangulating someone. The imprint was removed from the dummy, and their hands were photographed. Five imprints were randomly chosen and superimposed on the hand photographs in blind trials. In no cases did we match an imprint to the correct hand. However, in four cases we matched the imprint with several hands, one of which was the correct one. This means we were able to exclude nonmatches in 4/5 cases. Overall, matching of hands and fingermarks is difficult and inconclusive. Objective criteria for matching are difficult to establish, and matching is probably best suited for cases with specific anatomical features.

Asphyxia↗

PubMed2005

Thickness of the human cranial diploe in relation to age, sex and general body build.

BACKGROUND: Earlier studies have addressed the human total cranial vault thickness and generally found no correlation with sex, age or body weight. However, the thickness of the diploe has not been investigated. Our study has determined the diploeic thickness of the human cranial vault using modern autopsy material. METHODS: The diploeic bone thickness was measured in 64 individuals (43 males, 21 females) autopsied at our institute. The thickness was measured by X-raying biopsies trephined at four specific locations on the skull. Complete medical records and pathologic autopsy results were available. RESULTS: There was a statistically significant difference in diploeic thickness between males and females in the frontal region only. Diploeic thickness was highly correlated with total cranial vault bone thickness, except for the left euryon in females. Subsequent analyses failed to reveal any correlations between the diploeic thickness and age and height and weight of the individual. CONCLUSION: Males overall have a thicker diploe, albeit this difference is statistically significant only in the frontal region. We could not discern any trends as pertains to diploeic thickness versus age, height or weight. Since the thickness of the diploe may be an important parameter in biomechanical modelling of the cranial vault, this means that the diploe can be built into such models based on the total cranial thickness, except for the frontal region where the sexual dimorphism must be taken into account. Our findings are consistent with previous studies relating the total cranial thickness to the same parameters, in that we found a high correlation between diploeic and total cranial thickness (except at the left euryon for females). Finally, we recommend that future studies try to incorporate CT or MR scan imaging, rather than point sampling, in order to achieve a total assessment of the dimensionalities of the diploe.

Adult↗

PubMed2005

Lateral angle: a method for sexing using the petrous bone.

We report on the results of applying the so-called lateral angle method for sex determination on skeletal remains. The lateral angle denotes the angle of the internal auditory canal in relation to the medial surface of the petrous part of the temporal bone. The method involves making a small cast of the proximal part of the internal acoustic canal and determining the angle at which the canal opens up to the surface of the petrous bone. The method has the great advantage of utilizing one of the sturdiest bone elements of the human skeleton, and may thus be especially suited for analyses of very fragmented skeletal remains or cremated bones, where the petrous bone may still be readily recognizable. The method was tested using a forensic sample of 113 petrous bones with known sex. Intra- and interobserver testing was also performed. We found a statistically significant difference in angle size between males and females (mean angle size of males, 39.3 degrees ; mean angle size of females, 48.2 degrees ; P < 0.001). There was no bilateral difference in angle size. In blind trials, 83.2% of petrous bones were assigned to the correct sex. We also tested the lateral angle method against an archaeological skeletal sample. True sex was not known for this sample; instead, sexing had been carried out by assessing pelvic and cranial morphology in independent trials. We found a higher concordance between the lateral angle and "pelvic" sex than for lateral angle and "cranial" sex. Finally, we note that subadult sexing may also be possible with this method.

Adult↗

PubMed2005

mtDNA analysis of human remains from an early Danish Christian cemetery.

One of Denmark's earliest Christian cemeteries is Kongemarken, dating to around AD 1000-1250. A feature of early Scandinavian Christian cemeteries is sex segregation, with females buried on the northern sides and males on the southern sides. However, such separation was never complete; in the few early Christian cemeteries excavated in Scandinavia, there were always a few males placed on the north side, and some females on the south side. At Kongemarken, several males with juxtaposed females were found on the north side of the cemetery. Thus, to evaluate possible kinship relationships, and more general questions of population affinity, we analyzed mitochondrial DNA extracted from nine individuals excavated in two different areas within the cemetery: one male and four females from Area 1, and one male and three females from Area 2. Using stringent laboratory protocols, each individual was unequivocally assigned to a mitochondrial haplogroup. A surprising amount of haplogroup diversity was observed (Area 1: 1 U7 (male), 1 H, 1 I, 1 J, and 1 T2; Area 2: 2 H, 1 I, and 1 T, with one H being male); even the three subjects of haplogroup H were of different subtypes. This indicates that no subjects within each area were maternally related. The observed haplogroup, U7, while common in India and in western Siberian tribes, was not previously observed among present-day ethnic Scandinavians, and haplogroup I is rare (2%) in Scandinavia. These observations suggest that the individuals living in the Roskilde region 1,000 years ago were not all members of a tightly knit local population and comprised individuals with genetic links with populations that were from much farther away.

Age Determination by Skeleton↗

PubMed2005

Person identification by gait analysis and photogrammetry.

Surveillance images from a bank robbery were analyzed and compared with images of a suspect. Based on general bodily features, gait and anthropometric measurements, we were able to conclude that one of the perpetrators showed strong resemblance to the suspect. Both exhibited a gait characterized by hyperextension of the leg joints, and bodily measurements did not differ by more than 6 mm on average. The latter was quantified by photogrammetry: i.e., measuring by using images of the perpetrator as captured by surveillance cameras. Using the computer software Photomodeler Pro, synchronous images from different cameras were compared and concurrent body features were identified. The program could then render the perpetrator as a three dimensional, high-precision, scalable and measurable object.

Adult↗

PubMed2004

Absence of Yersinia pestis-specific DNA in human teeth from five European excavations of putative plague victims.

This study reports the results of a collaborative study undertaken by two independent research groups to (a) confirm recent PCR-based detection of Yersinia pestis DNA in human teeth from medieval plague victims in France, and (b) to extend these observations over five different European burial sites believed to contain plague victims dating from the late 13th to 17th centuries. Several different sets of primers were used, including those previously documented to yield positive results on ancient DNA extracts. No Y. pestis DNA could be amplified from DNA extracted from 108 teeth belonging to 61 individuals, despite the amplification of numerous other bacterial DNA sequences. Several methods of extracting dentine prior to the DNA extraction were also compared. PCR for bacterial 16S rDNA indicated the presence of multiple bacterial species in 23 out of 27 teeth DNA extracts where dentine was extracted using previously described methods. In comparison, positive results were obtained from only five out of 44 teeth DNA extracts for which a novel contamination-minimizing embedding technique was used. Therefore, high levels of environmental bacterial DNA are present in DNA extracts where previously described methods of tooth manipulation are used. To conclude, the absence of Y. pestis-specific DNA in an exhaustive search using specimens from multiple putative European plague burial sites does not allow us to confirm the identification of Y. pestis as the aetiological agent of the Black Death and subsequent plagues. In addition, the utility of the published tooth-based ancient DNA technique used to diagnose fatal bacteraemias in historical epidemics still awaits independent corroboration.

Base Sequence↗

PubMed2003

Y-chromosomal STR haplotypes in Inuit and Danish population samples.

Nineteen Y-chromosomal short tandem repeats (STRs), DYS19, DYS389-I, DYS389-II, DYS390, DYS391, DYS392, DYS393, DYS385, DYS388, DYS434, DYS435, DYS436, DYS437, DYS438, DYS439, DYS460, DYS461 and DYS462 were typed in Inuit (n=70) and Danish (n=62) population samples.

Chromosomes, Human, Y↗

PubMed2003

High level of male-biased Scandinavian admixture in Greenlandic Inuit shown by Y-chromosomal analysis.

We have used binary markers and microsatellites on the Y chromosome to analyse diversity in a sample of Greenlandic Inuit males. This sample contains Y chromosomes typical of those found in European populations. Because the Y chromosome has a unique and robust phylogeny of a time depth that precedes the split between European and Native American populations, it is possible to assign chromosomes in an admixed population to either continental source. On this basis, 58+/-6% of these Y chromosomes have been assigned to a European origin. The high proportion of European Y chromosomes contrasts with a complete absence of European mitochondrial DNA and indicates strongly male-biased European admixture into Inuit. Comparison of the European component of Inuit Y chromosomes with European population data suggests that they have their origins in Scandinavia. There are two potential source populations: Norse settlers from Iceland, who may have been assimilated 500 years ago, and the Danish-Norwegian colonists of the eighteenth century. Insufficient differentiation between modern Icelandic and Danish Y chromosomes means that a choice between these cannot be made on the basis of diversity analysis. However, the extreme sex bias in the admixture makes the later event more likely as the source.

Asian People↗

PubMed2003

Brief communication: age and fractal dimensions of human sagittal and coronal sutures.

The fractal dimensions of human sagittal and coronal sutures were calculated on 31 complete skulls from the Terry Collection. The aim was to investigate whether the fractal dimension, relying on the whole sutural length, might yield a better description of age-related changes in sutural morphology, as opposed to other methods of quantification, which generally rely on more arbitrary scoring systems. However, the fractal dimension did not yield better age correlations than other previously described methods. At best, the results reflected the general observation that young adults below age 40 years display an age-related development, but that it is impossible to arrive at any precise age determinations for older adults. It seems that for some individuals, suture obliteration simply does not take place, even at an advanced age, whereas for others, suture obliteration progresses rapidly. Until a better understanding of sutural biology is reached, this will render cranial sutures only marginally useful in age determination. This does not mean, however, that investigations should not be made to elucidate more unbiased methods of sutural morphology quantification.

Adult↗

PubMed2003

Facial image identification using Photomodeler.

We present the results of a preliminary study on the use of 3-D software (Photomodeler) for identification purposes. Perpetrators may be photographed or filmed by surveillance systems. The police may wish to have these images compared to photographs of suspects. The surveillance imagery will often consist of many images of the same person taken from different angles. We wanted to see if it was possible to combine such a suite of images in useful 3-D renderings of facial proportions.Fifteen male adults were photographed from four different angles. Based on these photographs, a 3-D wireframe model was produced by Photomodeler. The wireframe models were then rotated to full lateral and frontal views, and compared to like sets of photographs of the subjects. In blind trials, 9/15 of the wireframe models were assigned to the correct sets of photographs. In five/15 cases, the wireframe models were assigned to several sets, including the correct set. Only in one case was a wireframe model not assigned to a correct set of photographs at all.

Face↗

PubMed2002

Characterization of genetic miscoding lesions caused by postmortem damage.

The spectrum of postmortem damage in mitochondrial DNA was analyzed in a large data set of cloned sequences from ancient human specimens. The most common forms of damage observed are two complementary groups of transitions, termed "type 1" (adenine-->guanine/thymine-->cytosine) and "type 2" (cytosine-->thymine/guanine-->adenine). Single-primer extension PCR and enzymatic digestion with uracil-N-glycosylase confirm that each of these groups of transitions result from a single event, the deamination of adenine to hypoxanthine, and cytosine to uracil, respectively. The predominant form of transition-manifested damage varies by sample, though a marked bias toward type 2 is observed with increasing amounts of damage. The two transition types can be used to identify the original strand, light (L) or heavy (H), on which the initial damage event occurred, and this can increase the number of detected jumping-PCR artifacts by up to 80%. No bias toward H-strand-specific damage events is noted within the hypervariable 1 region of human mitochondria, suggesting the rapid postmortem degradation of the secondary displacement (D-loop) H strand. The data also indicate that, as damage increases within a sample, fewer H strands retain the ability to act as templates for enzymatic amplification. Last, a significant correlation between archaeological site and sample-specific level of DNA damage was detected.

Archaeology↗

PubMed2002

Distribution patterns of postmortem damage in human mitochondrial DNA.

The distribution of postmortem damage in mitochondrial DNA retrieved from 37 ancient human DNA samples was analyzed by cloning and was compared with a selection of published animal data. A relative rate of damage (rho(v)) was calculated for nucleotide positions within the human hypervariable region 1 (HVR1) and cytochrome oxidase subunit III genes. A comparison of damaged sites within and between the regions reveals that damage hotspots exist and that, in the HVR1, these correlate with sites known to have high in vivo mutation rates. Conversely, HVR1 subregions with known structural function, such as MT5, have lower in vivo mutation rates and lower postmortem-damage rates. The postmortem data also identify a possible functional subregion of the HVR1, termed "low-diversity 1," through the lack of sequence damage. The amount of postmortem damage observed in mitochondrial coding regions was significantly lower than in the HVR1, and, although hotspots were noted, these did not correlate with codon position. Finally, a simple method for the identification of incorrect archaeological haplogroup designations is introduced, on the basis of the observed spectrum of postmortem damage.

Animals↗