P-230
Multiplexing
autosomal and Y-STRs loci as a powerful tool for solving old a new criminal
cases
Pizzamiglio M1, Marino
A1, Stabile M1 and Garofano L1
1 Raggruppamento Carabinieri Investigazioni
Scientifiche, Reparto di Parma, Italy
In this paper we
refer to a partial DNA match, from evidence linked to two different robberies
occurring almost three years apart, in two different and distant towns in Northern Italy.
According to these
results, we decided to reanalyse the evidence still available, with both
IdentifilerTM by ABD and
Powerplex 16TM by Promega, in order to verify a possible parentage.
We also submitted our evidence to the new Yfiler Kit by ABD. The results we
obtained were the following:
-
12 STRs loci out of 17, identical in both
sets of evidence ;
-
5 STRs loci exhibiting one allele in
common ;
-
16 Y-STRs loci identical in both evidence
sets, showing the same haplotype.
This supported the
hypothesis that parentage was more than likely and gave strong support to the
investigation, allowing police to identify and arrest the guilty parties at a
later date.
Once more, it is
to be stressed that when we are faced with criminal investigations it is strongly
recommended to examine a large number of both autosomal STRs as well as
Y-STRs. This is the only way for
forensic scientists to obtain the most complete genetic information possible
and be able to assist in difficult and complex investigations, especially when
only degraded or very small samples are available.
lugaro@tin.it
P-231
The
use of Y STRs in rape cases associated to kinship relation
Pizzamiglio M1, Marino A1, Tempesta P1 and Garofano L1.
1 Raggruppamento Carabinieri Investigazioni Scientifiche,
Reparto di Parma, Italy
The
aim of this study is to show the usefulness obtained by combining autosomal and
Y STRs in casework, especially when faced with rapes in which we commonly have
to analyse male/female mixed material. In particular, we refer to two rape
cases in which, starting from the partial match coming from the autosomal STRs,
applied on the exhibits, we decided to run the Y STRs. This allowed us to
provide additional information based on parentage hypothesis that proved to be
essential for investigation and the subsequent identification of the culprits.
lugaro@tin.it
P-232
DNA
typing from a persimmon helps solve a murder case
Pizzamiglio M1, Marino A1, Tullio V1,
Denari D1 and Garofano L1.
1 Raggruppamento Carabinieri
Investigazioni Scientifiche, Reparto di Parma, Italy
As
is well known, saliva is nowadays considered good evidence from which to obtain
full DNA profiles. In this case we report about a murder in a small village
near Venice in
which, among other exhibits, a persimmon was collected from the garden outside
the crime scene. The fruit had been bitten into by someone linked to the
murder, just before he entered the victim’s house.
Due to the consistency of the persimmon, and
the DNA degradation caused by bacteria and fungi easily proliferated in the
sugar content of the fruit, we decided to sample the small amount of saliva
left by the suspect, with three dacron swabs, gently rubbed on the fruit, as
soon as the evidence came into our lab. We then proceeded with DNA extraction,
quantification, amplification and typing by multiplex STRs analyses, using the
commercially available kits.
A
complete STR profile was obtained from two out of three of the swabs used. This
profile was then compared with several individuals and allowed us to identify
the person who bit into the fruit. This person was then interrogated, and he
not only admitted his guilt but also
gave to the police new leads which allowed them to catch the rest of the gang.
lugaro@tin.it
P-233
AmpFℓSTR® Y-filer™: a new tool for rapid Y-str forensic haplotyping
Pontes ML1, Abrantes D1, Lima
G1, Cainé L1, Pereira MJ1, Matos
P1, Pinheiro MF1,2
1Instituto Nacional de Medicina Legal –
Delegação do Porto
2Faculdade de Ciências da Saúde –
Universidade Fernando Pessoa
In addition to the standard
panel of autosomal loci used in
forensic genetics, Y-STR haplotyping gives the ability to sensitive typing of
male-specific DNA especially in sexual assault cases or other situations where
mixtures of male and female cells are present. Within the last years a number
of Y-STR multiplex assays have been developed, most of them involving six or
fewer loci, with some exceptions.
Recently a new commercial kit has been available, the AmpFℓSTR® Y-filer™ PCR
amplification kit (Applied Biosystems) that permits the simultaneous
amplification of 17 Y-STR loci,
including all the markers in the actually used European “extended haplotype”
(DYS19, DYS189I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385I/II, DYS438
and DYS439) and also DYS437, DYS448, DYS456, DYS458, DYS635 and Y GATA H4. The
DNA was extracted from healthy unrelated males from peripheral blood and oral
swabs samples, using different methods (Chelex and phenol-chloroform). The amplified
products were detected on the ABI PRISM® 3100 genetic analyser (Applied
Biosystems). Fragment sizes were determined automatically using the Genescan® Anlysis Software v
3.7 and allele designations using Genetyper® Software v. 3.7 (Applied
Biosystems). We present population data using this new kit, in order to apply
it in our routine work.
Contact: Biologia@dpinml.mj.pt
P-234
Beware; gloves
and equipment used during the examination of exhibits are potential vectors for
transfer of DNA-containing material
Poy A, van Oorschot RAH
Victoria Police Forensic Services
Department, Victoria
3085, Australia
Gloves are worn during the examination of exhibits in
forensic biology laboratories. They are worn to protect the wearer from harmful
agents and to protect the exhibit from contamination by DNA-containing material
derived from the surface of the hand of the examiner. Changing of gloves
between handling of different exhibits is common practice. Gloved hands however
are capable of picking-up DNA-containing material from exhibits being examined
and transferring this to other areas of the exhibit and/or tools being utilised
whilst examining. If these tools are not adequately cleaned after examination
of a particular exhibit they may become a potential vector for future pick-up
and transfer of DNA derived from an exhibit examined earlier to a subsequently
examined exhibit. Items that come into direct contact with exhibits such as
scissor blades and forcep tongues are routinely cleaned between exhibit examinations,
however, their handles, containers, tissue boxes, pipettes, examination lamps
etc, that are touched by gloved hands during examination, may not.
Swabbings or tape-lifts of numerous objects that may
be used or touched during the examination of an exhibit revealed that only a
few provided sufficient DNA from which profiles could be generated. None of
those in the highest risk category (i.e. those that could pose a direct
transfer risk) contained sufficient DNA from which a full DNA profile could be generated.
We found that gloves can pick-up DNA-containing material while examining
exhibits and when touching other surfaces known to be contaminated with
DNA-containing material. We highlight a situation where a swabbing of the top
of a flexible examination lamp attached to an examination bench revealed a
strong Profiler Plus DNA profile from a single individual that matched the
profile from samples taken from a jacket that was examined on the bench
associated with the lamp three months prior to the swabbing of the lamp.
It is recommended that examiners of exhibits from
which samples may be taken for DNA analysis regularly change their gloves
whilst examining exhibits, avoid contact with areas of the exhibit that are
likely to be sampled for DNA analysis and to regularly clean tools and objects
that they may come into contact with while examining exhibits. This is
especially so for cases involving trace quantities of DNA.
P-235
High-Resolution analysis of Y-SNPs in three
populations from São Tomé and Príncipe
Prata MJ1,2, Tavares L1,2,
Trovoada MJ 1,3, Gusmão L 1, Beleza S 1, Alves
C 1, Amorim A 1,2
1Instituto de Patologia e Imunologia Molecular
da Universidade do Porto
2Faculdade de Ciências da Universidade do Porto
3Departamento de Antropologia da Universidade de
Coimbra
São Tomé e Príncipe is a small
archipelago situated in the Gulf
of Guinea whose
population history traces back to the end of the XV century when Portuguese
navigators discovered the previously uninhabited islands. The first settlers
were a few Europeans, mainly from Portugal, but the major
contribution to the peopling of São Tomé e Príncipe was from African slaves
brought, originally, from the mainland Western coast.
A very informative tool for
recovering the origin and history of human populations is the analysis of
patterns of genetic variation in contemporaneous populations. In previous
studies we have used mtDNA and Y-STRs to characterise Angolares, Forros and Tongas, three
population groups from São Tomé e Príncipe.
In order to obtain a better understanding of
the demographic history of the archipelago, here we have analysed 20
Y-chromosome biallelic polymorphisms (YAP, SRY8299, 92R7, SRY1532, SRY2627,
Tat, sY81, M9, LLy22g, 12f2, M109, M112, M150, M168, M213, M170, M201, M81 M78
and M269) in samples from Angolares (N=56), Forros (N=39) and Tongas (N=44).
As expected, most male
lineages belonged to sub-Saharan haplogroups. However, in the whole sample from
the archipelago the component of European origin reached approximately 20% in
the male pool of SNP-defined lineages, contrasting with the virtual absence
previously reported for the mtDNA female counterpart. The lowest percentage of
putative male European ancestry was registered among the Angolares, reflecting
the long history of relative isolation of the group. Globally, the Y-SNP data
now obtained, afforded a significant contribution to improve the knowledge
about the admixture process between Europeans and Africans that took place in
São Tomé e Príncipe.
P-236
Y-chromosome haplotypes and
male isonymy:
genetic and genealogical study
in a small town of Tuscany
(Buti, Italy)
1Center of Statistical Genetics, University
of Pisa, Italy
2Unit of Legal Medicine, School
of Medicine, University of Pisa, Italy
Introduction. In societies that use patrilineal family
denominations, surnames and Y-chromosome haplotypes (YCH) follow a common
pattern of inheritance. Therefore, isonymous individuals are expected to carry
the same YCH, and observed inconsistencies can be ascribed to gene mutations,
illegitimacies, surname polyphyletic origin, or transcription errors in the
civic records. To investigate these issues in a well-defined population, we
selected the village
of Buti, near Pisa. This small town
(about 5,000 inhabitants) maintains lively historical traditions; oral
anecdotes report high level of reproductive isolation from the neighboring
area. The mayor and the municipality council encouraged participation in the
research.
Material and methods. A consent form has been approved by the IRB of
the University of
Pisa. Volunteers sign it
when they donate blood or saliva for the present project at a local health
facility. The entire civic records of the municipality have been acquired. In
addition, the parochial archives of the main church of the village are almost
intact, and were consulted for tracing specific surname genealogies back to the
sixteenth century. YCHs of 12 STR markers were determined by the Y-system
Promega ® commercial kit.
Results. To date, 69 males participated in the study; the
sampling campaign is still open. The vast majority of the volunteers declared
that all four grandparents were born in the village. Here, we report on the
subjects whose surname occurred more than once in the sample, and who were
unable to specify the degree of relationship with their isonymous fellow
citizens. This subsample included 36 subjects distributed among 13 different
surnames. Seven surnames (20 subjects) did not show variation of YCH among
isonymous individuals, whereas 6 surnames (16 subjects) showed one or more
locus difference, as follows:
·
surname Blue included 5 subjects; two of whom carried an allele of
DYS391 differing of one repeat unit from the allele of the other three, whereas
another subject carried an allele of DYS392 differing of one unit from the
other four; their genealogy has been reconstructed back to a founder individual
(the most recent common ancestor, MRCA) who moved into the village at the end
of the 16th century, the total number of meioses separating the MRCA
from these five present-day descendants was 37;
·
surname Pink included 3 subjects, two of whom were identical but a
single step difference at locus DYS390, the other totaling 14 and 15 step
differences with the first two at seven loci;
·
surnames White, Brown and Yellow included two subjects each, and showed
a single step difference for the loci DYS390, DYS391, and DYS385, respectively;
·
surname Green included two subjects, differing for a total of 11
mutational steps in nine loci. Interestingly, one of these haplotypes was
identical to a haplotype observed in Pink.
Conclusions. Among 13 different surnames including at least a
pair of isonymous individuals (36 total subjects), we were able to identify six
single-step mutations (two in DYS391, the others in DYS385, DYS390, DYS392 and
DYS393) and two cases of historical illegitimacies. Our approach shall allow us
to estimate mutation rates at STR loci with high accuracy.
Contact:
sprex@biomed.unipi.it
P-237
An
unusual case of disputed paternity: predicting the effect of typing multiple
siblings
1Center of Statistical Genetics, University of Pisa, Italy
2Unit of Legal Medicine, School of Medicine,
University of Pisa, Italy
The following case of disputed paternity has come at
our attention recently. The claimant pretended to be the natural daughter of a
man long deceased, survived by six legitimate children. The judiciary question
verged on the probabilities of paternity exclusion (in case of false
parenthood) or attribution (in case of true parenthood), provided that all the
six defendants contributed their DNA for genotyping.
In case of false parenthood, incompatibility can occur
only when four different alleles are present among the legitimate siblings and
none of these is present in claimant’s genotype. We calculated the probability
of this occurrence both by an analytical method and by computer simulation. We
assumed that 20 STRs were available for the analysis. The two methods produced
overlapping results; in about 78% of the cases there was incompatibility in at
lest one locus, in 41% there was incompatibility in at least two loci, and only
in 14% of the cases there was incompatibility in at least three loci.
In case of true parenthood, we estimated the
probability distribution of the paternity index (PI) by computer simulation. We
obtained a probability of paternity higher than 0.999 in 99.7% of cases.
In conclusion, while in the hypothesis of false
kinship only in a small percentage of cases is it possible to obtain at least
three incompatibilities, in the opposite case of true fatherhood is it almost
certain to reach a value for the probability of paternity > 99,9%.
P-238
Experiments on the DNA contamination risk via
dactyloscopy brushes
Proff C, Schmitt C, Schneider PM, Rothschild MA
Institute of Legal Medicine, University Clinic Cologne, Germany
One of the crucial tasks of a crime scene investigation is the search for latent fingerprints. In addition to using chemicals, lasers, alternate light sources, and other physical means, one of the most common techniques for the detection and development of latent fingerprints is the use of carbon black powder.
As the analysis of small
amounts of DNA has been improved especially in the last years using "low
copy number" typing strategies, the police more frequently requests DNA
testing of latent fingerprints that are not analyzable for dactyloscopy because
of smearing or incompleteness. Often enough this is the last possibility to
obtain crucial information leading to a suspect by database search or to match
evidence to a suspect.
In contrast to other contact
stains taken directly from the evidence, latent fingerprints have normally been
treated with powder using dactyloscopy brushes made from glass fibers or bird
feathers. According to SOCO´s from the Cologne Police Department these brushes
are typically used for several weeks up to months on numerous different crime
scenes. This led us to the assumption that DNA from powder-treated fingerprints
may be contaminated by DNA from other crime scenes or other evidence from the
same crime scene. The area for visualization of fingerprints is selected
arbitrarily which means even huge surfaces (e.g. doors) are treated with
powder, and even when no fingerprint was found, human cells (e.g. skin debris,
saliva) may adhere to the brush.
In a first study 14 used
fingerprint brushes were obtained from police investigators and subjected to
DNA analysis using standard multiplex STR typing kits. We found human DNA
traces on 12 of these, partially with high amounts of DNA. Typing results using
standard STR multiplex analysis mostly showed DNA mixtures from two or more
persons. In one case, however, a full DNA profile from a single person was
detected with high signal intensities suggesting that it may have arisen from a
blood or saliva stain.
However, these results are not
suitable to demonstrate the transfer of DNA adhering to the brush to a fresh
fingerprint. To address the question whether such a secondary transfer from
dactyloscopy brushes to other surfaces and fingerprints can be observed,
experiments with artificially contaminated and used fingerprint brushes were
carried out.
Address
for correspondence:
Dr.
Carsten Proff, Institute of Legal Medicine, Melatenguertel 60-62, 50823 Cologne,
Germany;
phone +49 221 47886623, fax +49 221 4783496, e-mail: carsten.proff@uk-koeln.de
phone +49 221 47886623, fax +49 221 4783496, e-mail: carsten.proff@uk-koeln.de
P-239
Work in progress –
Applied Biosystems GeneMapperID®
Proff C
Institute of Legal Medicine, University Clinic Cologne, Germany
The GeneMapperID® software solution for forensic identity testing is finding its way into more and more laboratories worldwide. Replacing the time consuming GeneScan® and/or Genotyper® software one expected to purchase a modern easy-to-use software that performs high quality genotyping and provides a wide range of options in the field of forensic DNA testing.
After giving a short overview
on the software options, our experiences after working with the GeneMapperID®
for more than one year are going to be presented. These experiences comprise
the advances in comparison with formerly used GeneScan® and/or Genotyper®, the
software handling, observed software bugs and improvement suggestions.
Besides this, a critical appraisal on Applied Biosystems' policy
concerning the ongoing restrictions through so-called ‘integrated solutions’ is
made. The user is forced to spend a lot of time to adopt previously used
protocols, matrices and run methods on their machines for use with the newer
software versions and technical solutions, such as new Matrix Standards, Data collection
or GeneMapperID® versions 3.1 and 3.2. In some cases,
"integration" appears to offer predefined solutions which complicate
or even prevent user-defined control of the sample processing. As many users
are confronted with these developments a critical discussion is necessary.
Address for
correspondence:
Dr. Carsten Proff, Institute of Legal Medicine,
Melatenguertel 60-62, 50823 Cologne, Germany;
phone +49 221 47886623, fax +49 221 4783496, e-mail: carsten.proff@uk-koeln.de
phone +49 221 47886623, fax +49 221 4783496, e-mail: carsten.proff@uk-koeln.de
P-240
Monte
Carlo Bayesian Identification Using STR Profiles
Promish
DI
The method described here
bears out the premise that a complete CODIS 13 STR profile contains all the
information needed to establish the probability of identity of two individuals
having the same profile. In order to do so, the method combines
three concepts: the concept of the culprit as a member of a
group; the concept of the suspect as a one-person group; and the
concept of groups, other than the suspect, which are distinguishable
only by their homozygosity. This presentation shows how to perform a
Bayesian analysis of an STR profile with respect to the suspect group and a
random sample of non-suspect groups. It demonstrates the robustness of
the method with respect to a varied selection of real profiles and with respect
to evidence other than the profiles.
The Monte Carlo Bayesian
(MCB) method described here has several features worth noting.
(a) The method is
case-specific. Both evaluation of and
adjustment for substructure are automatic, and they are unique to the STR
profile at issue.
(b) The method accommodates
variation in prior probabilities according to the investigator's judgment
regarding non-profile data.
(c) The method produces probabilities
not likelihood ratios.
(d) The method does not
rely on reference group allele frequency data.
The investigator can use the method when she/he lacks either knowledge
of, or immediate access to, suitable frequency data.
In addition to the features
mentioned above, the case analysis results shown in this presentation lead,
through a series of subordinate conclusions,
to one major one.
Here are the subordinate
conclusions.
(a) The results of a Monte Carlo Bayesian (MCB)
analysis appear to be consistent with what an experienced investigator might
infer by inspection.
(b) Because MCB relies only on within-locus
allele differences, it can analyse encrypted (real) profiles. It thus has potential for use where personal
privacy is of concern.
(c) Consequently, MCB can also analyse synthetic
profiles, such as the extreme case of an individual who is homozygous at all of
the CODIS 13 loci. The results of such a
case lead to the following major conclusion.
It seems safe to say that
any "cold hit", regardless of
substructure, is at least a very good
investigative lead; and that a profile
match coupled with a "minimum probable cause" prior amounts to an
investigative, if not a juridical, certainty.
Because the initial work on
this subject tacitly assumed that crime scenes yield complete CODIS 13
profiles, this presentation will explore the sensitivity of MCB to reduction of
the profile, particularly by elimination of the more informative loci.
P-241
Efficiency comparison of seven different Taq
polymerases used in hemogenetics.
Purzycka JK 1,
Olewiecki I 1, Soltyszewski I 1, Pepinski W 2,
Janica J 2
1 Central Forensic Laboratory of
Police, Warsaw,
Poland1
2 Department of Forensic
Medicine, Medical University of
Bialystok, Poland
Currently, STR typing is the most efficient and the fastest way for
identification of biological material samples from humans. Automated analysis
of dye-marked PCR products processed during capillary electrophoresis provides
with accurate and precise results. However, efficacy of DNA analysis largely
depends on DNA degradation which is related with sample aging and storage
conditions. Objective of the study was to compare the enzymatic efficiency of
polymerases used for analysis of degraded low concentration DNA templates. Nine
different polymerase brands have been used: AmpliTaq Gold DNA Polymerase
(Applera), OptiTaq DNA (EURx), Taq DNA Polymerase (EURx), Perpetual Taq DNA Polymerase
(EURx), DNA
Polymerase (Biotools), DNA Polymerase - Gel form (Biotools), Platinum Taq DNA
Polymerase (Invitrogen), Taq DNA Polymerase, Recombinant (Invitrogen),
JumpStart Taq DNA Polymerase (Sigma). DNA was extracted by organic method from
dried blood samples collected from 30 non-related individuals in 1955 at the
Department of Forensic Medicine, Medical University of Bialystok. The samples
were stored in paper envelopes at room temperature and constant humidity.
Recovered DNA was quantitiated fluorometrically using PicoGreen dsDNA
Quantitation Reagent (Molecular Probes) and Fluoroscan Ascent FL (Labsystems).
DNA quality was assessed by 2% ethidium bromide agarose gel electrophoresis.
Different amounts of DNA from 0.25 to 1.25 ng were used as a PCR template.
AmpFlSTR SGM Plus kit and ABI 3100 Sequencer (Applera) were used to obtain
genetic profiles. Significant differences in polymerase efficiency in relation
to DNA template degradation were observed.
P-242
Cytochrome b. An alternative to cytochrome oxidase
as a species-specific marker in Forensics
Ramos de Pablo R1,2, Saloña M2,
Sarasola E1,2, Sergio Cardoso S1,2 and Martínez de
Pancorbo M1,2
1Servicio de Genómica:
Banco de ADN. Universidad del País Vasco. Vitoria-Gasteiz. Spain
2Dpto. de Zoología y
Biología Celular Animal. Universidad del País Vasco. Leioa (Bizkaia). Spain
Several DNA sequences such as
those belonging to the mitochondrial genome (e.g. cytochrome b) comprise
species-specific information which has shown to be a quick and reliable choice
in forensic as well as in phylogenetic investigations (Parson et al. Int J
Legal Med. 2000; 114: 23-28). Methodologies based on these type of sequences,
allow the identification of carrion flies specimens which is a fundamental
first task in forensic entomological studies. Unfortunately, species are
frequently rather difficult to establish, since (a) adults may have not been
collected during a forensic prospect and (b) eggs and larvae are fairly hard to
distinguish morphologically at specific level until they have not been
developed to adults.
The purpose of this work has been to develop a proper methodology based
on mitochondrial cytochrome b gene to allow the identification of entomological
species pertaining to forensic casework.
To achieve this goal, seventeen third-instar larvae previously identified
as Steribia nigriceps by morphological means, were utilized. DNA
was extracted as follows: cell lysis was performed using proteinase K and SDS.
Next, DNA was purified using the phenol/chloroform method. A 358 bp fragment of
the cytochrome b was amplified via PCR under adjusted conditions after Parson
et al. (2000). All the samples were sequenced in an automatic ABI
Prism 310 DNA sequencer. PCR products were separated by electrophoresis in
agarose gels stained with ethidium bromide and visualised under
UV-illumination.
A
consensus sequence of 305 bp was obtained from the aforementioned procedure.
Then, this sequence was submitted to a BLAST search at NCBI (www.ncbi.nlm.nih.gov/BLAST). This process permitted to locate the
nearest species, and so work on phylogenetic studies. It is important to
highlight that there is a sequence of 86 bp which is equal in all the studied
specimens genome. This unique characteristic could be utilized as a
species-specific marker for this species, as it only possesses dissimilarities
at the interspecific level. These results indicate that
the characterization of insects via the mitochondrial cytochrome b gene is
fairly trustworthy.
Contact: vitoriajulio2004@yahoo.es
P-243
Common Y-chromosomal STR database for three closely
related European populations
Rębała K1, Mikulich
AI2, Tsybovsky IS3, Siváková D4, Szczerkowska
Z1
1Department of
Forensic Medicine, Medical
University, Gdansk, Poland
2Institute for the
Study of Arts, Ethnography and Folklore, National Academy of Sciences,
Minsk, Belarus
3Institute of
Problems of Criminology, Criminalistics and Forensic Expertise, Minsk, Belarus
4Department of
Anthropology, Comenius
University, Bratislava, Slovakia
A unique inheritance pattern
and specificity to males has made the human Y-chromosomal short tandem repeat
(Y-STR) markers an excellent tool in male kinship analysis, genealogical
studies and discrimination of male DNA in male/female stain mixtures. However,
extensive analysis of Y-STR polymorphism throughout Europe
has shown significant differences in allele and haplotype distribution even
between closely related human populations. Therefore, establishment of a common
Y-STR haplotype frequency database for different European populations appeared
to be impossible. Since homogeneity of paternal lineages determined by analysis
of minimal haplotypes has been shown between 6 regional populations in Poland,
the aim of this study was to compare usefulness of 18 Y-chromosomal
microsatellites in forensic practice in the Polish population and two other
closely related Slavic populations of Belarus and Slovakia, and to check for
the possibility of the creation of a common Y-STR haplotype frequency database
for forensic purposes.Y-chromosomal microsatellites were genotyped in 568
randomly selected, unrelated males: 196 Belarusians, 208 Poles, and 164
Slovaks, by means of a multiplex (octadecaplex) PCR reaction and capillary
electrophoresis using an ABI Prism 310 Genetic Analyzer. The loci analysed
included DYS19, DYS388, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393,
DYS426, DYS437, DYS438, DYS439, DYS460, GATA H4.1, DYS385 a/b, and YCAII a/b.
Allele designation was based on comparison with the constructed allelic ladder.
In order to check for a marker’s potential for resolution of similar
haplotypes, contribution of each system to the discrimination capacity was
calculated. Analysis of molecular variance (AMOVA) was performed using Arlequin
2.000 software. Markers responsible for the differences between populations
were identified using a chi-square test for homogeneity and locus-by-locus
AMOVA. The overall haplotype diversity value ranged from 0.9982 in the Polish population to 0.9992 among Belarusians
and Slovaks, while discrimination capacity was 93.4%, 92.3%, and 94.5% for
Belarusians, Poles and Slovaks, respectively. The most polymorphic system was
DYS389 in the Belarusian population, whereas among Poles and Slovaks,
the highest gene diversity was found in DYS385. The most valuable marker in
discrimination of similar haplotypes was DYS389 while DYS426 and DYS438 did not
affect the discrimination power of the multiplex in all three populations.
AMOVA revealed significant differences between the populations and excluded
possibility of one common Y-STR database. Analysis of haplotypes defined only
by markers showing homogeneity within the three populations (DYS388, DYS389I,
DYS389II-I, DYS393, DYS426, DYS460, YCAII a/b) showed that the whole genetic
variation was attributable to the variation within populations and enabled
establishment of a common database with haplotype diversity equal to 0.9632. For databases combined for pairs of populations,
the number of available loci increased (up to 13 loci in case of a
Belarusian-Slovak database) and the power of discrimination was higher.
The studied Y-STR loci define very informative haplotypes for
population-genetic and forensic investigations. A constantly growing number of
Y-chromosomal microsatellites available for research enable selection of
markers for haplotype databases common for closely related populations, so that
discrimination power of such haplotypes may reach a level acceptable in
forensic casework.
Prof.
Zofia Szczerkowska, PhD Department
of Forensic Medicine, Medical
University of Gdansk
P-244
SampleCheck, an information management system for
quality assurance of DNA-profile analysis in parentage testing
Reitz P, Jung M
bj-diagnostik GmbH, Kerkrader Str.
11, 35394 Giessen, Germany
To increase the validity of
laboratory results SampleCheck performs plausibility checks on DNA profiles for
every batch processed. This platform independent programme interacts with a
database storing DNA profiles and further information. The main function of
SampleCheck is tp perform plausibility checks on DNA profiles of a batch to
detect pipetting errors, contaminations with other DNA and if samples during
collection or pipetting may have been interchanged. Checks can be performed
batchwise and/or against the whole database. Samples of each family in a batch
can also be checked for exclusions and exchanges. Every sample is monitored for
correct gender by comparing expected and measured gender. At the same time an
alignment of the measured profiles and the profiles of coworkers and positive
controls takes place. Additionally a single sample or the samples of a whole
batch can be checked for identical profiles and profiles sharing a common
allele on each marker like in father-child and mother-child relations. Allele
frequency tables for diferent populations, mutation rates, coworkers and
positive control profiles can be stored. SampleCheck enables the user to import
this information from different file formats to the database. LR-values can be
calculated using three different methods.
Contact: michael.jung@bj-diagnostik.de
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