ABI 310 Genetic Analyzer – a capillary electrophoresis instrument used by
forensic DNA laboratories to separate short tandem repeat (STR) loci on the basis
of their size.
Adenine – a purine base; one of the four molecules containing nitrogen present in
the nucleic acids DNA and RNA; designated by letter A.
Allele – one of two or more alternative forms of a gene.
Allele Frequency – the proportion of a particular allele among the chromosomes
carried by individuals in a population.
ASCLD (ascld.org) – American Society of Crime Laboratory Directors; involved
with accreditation of DNA testing labs.
Amino acid – Any of a class of 20 molecules that are combined to form proteins in
living things. The sequence of amino acids in a protein and hence protein function
are determined by the genetic code.
Amplification – An increase in the number of copies of a specific DNA fragment;
can be in vivo or in vitro.
Autosome – A chromosome not involved in sex determination. The diploid human
genome consists of 46 chromosomes, 22 pairs of autosomes, and one pair of sex
chromosomes (the X and Y chromosomes).
Base pair – two complementary nucleotides in DNA; base pairing occurs between
A and T and between G and C.
Base sequence – the order of nucleotide bases in a DNA molecule.
Base sequence analysis – a method, sometimes automated, for determining the
base sequence.
Biotechnology – a set of biological techniques developed through basic research
and now applied to research and product development.
Blind proficiency test – a proficiency test in which the laboratory personnel do not
know that a test is being conducted.
Capillary electrophoresis – a method that utilizes a narrow polymer-filled tube to
separate DNA molecules by size.
Ceiling principle – a conservative approach for estimating a DNA profile’s
frequency of occurrence in a population containing multiple ethnic groups.
Chromosome – a large piece of DNA. Humans have 23 different chromosomes in
almost every type of cell.
CODIS – Combined DNA Index System, established in 1998 and containing the
STR DNA profiles of many thousands of convicted offenders.
COfiler – PCR Amplification Kit (AmpFLSTR® COfiler™) that provide human
identification laboratories with the ability to generate information for six STR loci
and Amelogenin.
Thursday, June 16, 2011
Complementary sequences
Complementary sequences – nucleic acid base sequences that form a doublestranded structure by matching base pairs; the complementary sequence to G-T-AC is C-A-T-G.
Controls – tests performed in parallel with experimental samples and designed to
demonstrate that a test was reliable.
Cytosine – a pyrimidine base; one of the four molecules containing nitrogen
present in the nucleic acids DNA and RNA; designated by letter C.
Degradation – the chemical or physical breaking down of DNA.
Denaturation – the process of splitting the complementary double strands of DNA
to form single strands.
DNA (Deoxyribonucleic acid) – the genetic material.
Diploid – having two sets of chromosomes, one from each parent (compare
haploid).
DNA databank (database) – a collection of DNA typing profiles of selected or
randomly chosen individuals.
DNA polymerase – an enzyme that catalyzes the synthesis of double stranded
DNA.
DNA sequence – the relative order of base pairs, whether in a fragment of DNA, a
gene, a chromosome, or an entire genome.
Double Helix – the shape that two linear strands of DNA assume when bonded
together.
Dye blobs – a technical artifact associated with STR testing.
Electrophoresis – a technique in which different molecules are separated by their
rate of movement in an electric field.
Enzyme – a protein that can speed up a specific chemical reaction without being
changed or consumed in the process.
Gametic (phase) equilibrium – the state of loci on different chromosomes when
the allele at one locus in the gamete varies independently of that at the other loci.
Gel – matrix (often agarose or acrylamide) used in electrophoresis to separate
molecules.
Gene – the basic unit of heredity; a sequence of DNA nucleotides on a
chromosome.
Gene frequency – the relative occurrence of a particular allele in a population.
Gene mapping – determination of the relative positions of genes on a DNA
molecule (chromosome or plasmid) and of the distance, in linkage units or physical
units, between them.
Genetics – the study of the patterns of inheritance of specific traits.
Genetic drift – random fluctuation in allele frequencies due to small population
sizes (sampling error).
Genome – the sum total of an organism’s genetic material.
Controls – tests performed in parallel with experimental samples and designed to
demonstrate that a test was reliable.
Cytosine – a pyrimidine base; one of the four molecules containing nitrogen
present in the nucleic acids DNA and RNA; designated by letter C.
Degradation – the chemical or physical breaking down of DNA.
Denaturation – the process of splitting the complementary double strands of DNA
to form single strands.
DNA (Deoxyribonucleic acid) – the genetic material.
Diploid – having two sets of chromosomes, one from each parent (compare
haploid).
DNA databank (database) – a collection of DNA typing profiles of selected or
randomly chosen individuals.
DNA polymerase – an enzyme that catalyzes the synthesis of double stranded
DNA.
DNA sequence – the relative order of base pairs, whether in a fragment of DNA, a
gene, a chromosome, or an entire genome.
Double Helix – the shape that two linear strands of DNA assume when bonded
together.
Dye blobs – a technical artifact associated with STR testing.
Electrophoresis – a technique in which different molecules are separated by their
rate of movement in an electric field.
Enzyme – a protein that can speed up a specific chemical reaction without being
changed or consumed in the process.
Gametic (phase) equilibrium – the state of loci on different chromosomes when
the allele at one locus in the gamete varies independently of that at the other loci.
Gel – matrix (often agarose or acrylamide) used in electrophoresis to separate
molecules.
Gene – the basic unit of heredity; a sequence of DNA nucleotides on a
chromosome.
Gene frequency – the relative occurrence of a particular allele in a population.
Gene mapping – determination of the relative positions of genes on a DNA
molecule (chromosome or plasmid) and of the distance, in linkage units or physical
units, between them.
Genetics – the study of the patterns of inheritance of specific traits.
Genetic drift – random fluctuation in allele frequencies due to small population
sizes (sampling error).
Genome – the sum total of an organism’s genetic material.
Genome projects
Genome projects – Research and technology development efforts aimed at
mapping and sequencing some or all of the genome of an organism.
Genophiler™ – an automated, objective system for reviewing and presenting DNA
profiling data.
Genotype – the genetic makeup of an organism, as distinguished from its physical
appearance or phenotype.
Guanine – a purine base; one of the four molecules containing nitrogen present in
the nucleic acids DNA and RNA; designated by letter G.
Hardy-Weinberg equilibrium (HWE) –populations of organisms that are in HWE
have no statistical correlations between any pairs of alleles within individuals in
the population.
Heredity – the transmission of characteristics from one generation to the next.
Heterozygous – a heterozygous organism has two different alleles at a particular
locus.
Homozygous – a homozygous organism has two copies of the same allele at a
particular locus.
Identifiler – PCR Amplification Kit (AmpFLSTR® Identifiler™) that provides
human identification laboratories with the ability to generate information on 15
STR loci and Amelogenin.
In vitro – outside a living organism.
Kilobase (kb) – unit of length for DNA fragments equal to 1000 nucleotides.
Kinship coefficient – the probability that two randomly chosen genes, one from
each of two individuals in a population, are identical (i.e. both descended from the
same ancestral gene, or one from the other).
Linkage – the association of alleles at two or more loci due either to their residing
on a single chromosome or their abundance in a particular ethnic group that causes
them to appear together at a higher than expected frequency.
Localize – determination of the original position (locus) of a gene or other marker
on a chromosome.
Locus (pl. loci) – the physical location of a gene on a chromosome.
Marker – a gene of known location on a chromosome and phenotype that is used
as a point of reference in the mapping of other loci.
Matrix failure (pull up) – a result of the inability of the detection instrument to
properly resolve the dye colors used to label PCR amplification products. Often
due to off-scale peaks.
Megabase (Mb) – unit of length for DNA fragments equal to one million
nucleotides.
Mitochondrial DNA (mtDNA) – DNA found in the mitochondria inside cells (not
associated with the nuclear chromosomes); transmission is only from mother to
child.
mapping and sequencing some or all of the genome of an organism.
Genophiler™ – an automated, objective system for reviewing and presenting DNA
profiling data.
Genotype – the genetic makeup of an organism, as distinguished from its physical
appearance or phenotype.
Guanine – a purine base; one of the four molecules containing nitrogen present in
the nucleic acids DNA and RNA; designated by letter G.
Hardy-Weinberg equilibrium (HWE) –populations of organisms that are in HWE
have no statistical correlations between any pairs of alleles within individuals in
the population.
Heredity – the transmission of characteristics from one generation to the next.
Heterozygous – a heterozygous organism has two different alleles at a particular
locus.
Homozygous – a homozygous organism has two copies of the same allele at a
particular locus.
Identifiler – PCR Amplification Kit (AmpFLSTR® Identifiler™) that provides
human identification laboratories with the ability to generate information on 15
STR loci and Amelogenin.
In vitro – outside a living organism.
Kilobase (kb) – unit of length for DNA fragments equal to 1000 nucleotides.
Kinship coefficient – the probability that two randomly chosen genes, one from
each of two individuals in a population, are identical (i.e. both descended from the
same ancestral gene, or one from the other).
Linkage – the association of alleles at two or more loci due either to their residing
on a single chromosome or their abundance in a particular ethnic group that causes
them to appear together at a higher than expected frequency.
Localize – determination of the original position (locus) of a gene or other marker
on a chromosome.
Locus (pl. loci) – the physical location of a gene on a chromosome.
Marker – a gene of known location on a chromosome and phenotype that is used
as a point of reference in the mapping of other loci.
Matrix failure (pull up) – a result of the inability of the detection instrument to
properly resolve the dye colors used to label PCR amplification products. Often
due to off-scale peaks.
Megabase (Mb) – unit of length for DNA fragments equal to one million
nucleotides.
Mitochondrial DNA (mtDNA) – DNA found in the mitochondria inside cells (not
associated with the nuclear chromosomes); transmission is only from mother to
child.
Mitosis
Mitosis – the process of nuclear division in cells that produces daughter cells that
are genetically identical to each other and to the parent.
Multiplexing – a sequencing approach that uses several pooled samples
simultaneously, greatly increasing sequencing speed.
Mutation – any inheritable change in DNA sequence.
Nucleic acid – a nucleotide polymer that DNA and RNA are major types.
Nucleotide – chemical units that are strung together in long chains to make DNA
molecules.
Nucleus – the cellular organelle in eukaryotes that contains the genetic material.
Oncogene – a gene, one or more forms of which is associated with cancer. Many
oncogenes are involved, directly or indirectly, in controlling the rate of cell growth.
Physical map – a map of the locations of identifiable landmarks on DNA. Distance
is measured in base pairs.
PCR (polymerase chain reaction) – an amplification process that yields millions
of copies of desired DNA through repeated cycling of a reaction involving the
enzyme DNA polymerase.
Peak height imbalance – a significant difference (usually 30% or more) in the
amount of signal obtained for two alleles from a single STR locus that might be
suggestive of more than one contributor to a sample.
Polymorphic – a locus is polymorphic if a population contains two or more
detectable alleles.
Polymorphism – difference in DNA sequence among individuals. Genetic
variations occurring in more than 1% of a population would be considered useful
polymorphisms for linkage analysis.
Population – a group of individuals residing in a given area at a given time.
Primer – short preexisting polynucleotide chain to which new
deoxyribonucleotides can be added by DNA polymerase.
Probe – single-stranded DNA or RNA of a specific base sequence, labeled either
radioactively or immunology, that are used to detect the complementary base
sequence by hybridization.
Proficiency tests – tests to evaluate the performance of technicians and
laboratories; in open tests, the technicians are aware that they are being tested, but
in blind tests, they are not.
Profiler Plus – PCR Amplification Kit (The AmpFLSTR® Profiler Plus™) that
provides human identification laboratories with the ability to generate information
for nine polymorphic STR loci and the Amelogenin locus.
Protein – a large molecule composed of one or more chains of amino acids in a
specific order; the order is determined by the base sequence of nuceotides in the
gene coding for the protein. Proteins are required for the structure, function, and
regulation of the body cells, tissues, organs, and each protein has unique functions.
are genetically identical to each other and to the parent.
Multiplexing – a sequencing approach that uses several pooled samples
simultaneously, greatly increasing sequencing speed.
Mutation – any inheritable change in DNA sequence.
Nucleic acid – a nucleotide polymer that DNA and RNA are major types.
Nucleotide – chemical units that are strung together in long chains to make DNA
molecules.
Nucleus – the cellular organelle in eukaryotes that contains the genetic material.
Oncogene – a gene, one or more forms of which is associated with cancer. Many
oncogenes are involved, directly or indirectly, in controlling the rate of cell growth.
Physical map – a map of the locations of identifiable landmarks on DNA. Distance
is measured in base pairs.
PCR (polymerase chain reaction) – an amplification process that yields millions
of copies of desired DNA through repeated cycling of a reaction involving the
enzyme DNA polymerase.
Peak height imbalance – a significant difference (usually 30% or more) in the
amount of signal obtained for two alleles from a single STR locus that might be
suggestive of more than one contributor to a sample.
Polymorphic – a locus is polymorphic if a population contains two or more
detectable alleles.
Polymorphism – difference in DNA sequence among individuals. Genetic
variations occurring in more than 1% of a population would be considered useful
polymorphisms for linkage analysis.
Population – a group of individuals residing in a given area at a given time.
Primer – short preexisting polynucleotide chain to which new
deoxyribonucleotides can be added by DNA polymerase.
Probe – single-stranded DNA or RNA of a specific base sequence, labeled either
radioactively or immunology, that are used to detect the complementary base
sequence by hybridization.
Proficiency tests – tests to evaluate the performance of technicians and
laboratories; in open tests, the technicians are aware that they are being tested, but
in blind tests, they are not.
Profiler Plus – PCR Amplification Kit (The AmpFLSTR® Profiler Plus™) that
provides human identification laboratories with the ability to generate information
for nine polymorphic STR loci and the Amelogenin locus.
Protein – a large molecule composed of one or more chains of amino acids in a
specific order; the order is determined by the base sequence of nuceotides in the
gene coding for the protein. Proteins are required for the structure, function, and
regulation of the body cells, tissues, organs, and each protein has unique functions.
Random match probability –
Random match probability – the chance of a random match; as used in DNA
profiling, it is the probability that the DNA of a randomly chosen person has a
DNA profile that cannot be distinguished from that observed in an evidence
sample.
Recombinant DNA technologies – procedures used to join together DNA
sequences in a cell-free system. Under appropriate conditions, a recombinant DNA
molecule can enter a cell and replicate there, either autonomously or after it has
become integrated into a cellular chromosome.
Resolution – degree of molecular detail on a physical map of DNA.
Restriction enzyme – a protein that recognizes specific, short nucleotide sequences
and cuts DNA at those sites. Bacteria contain over 400 such enzymes that
recognize and cut over 100 DNA sequences.
Restriction fragment length polymorphism (RFLP) – variation between
individuals in DNA fragment sizes cut by specific restriction enzymes;
polymorphic sequences that result in RFLPs that are used as markers on both
physical maps and genetic linkage maps. RFLPs are usually caused by mutation at
a cutting site.
RFU (relative fluorescent units) – units of measure for the light intensity detected
by a fluorescence detector, correlated with the amount of DNA associated with a
particular STR allele.
Serology – a discipline that uses immunology to study body fluids.
Sequencing – determination of the order of nucleotides (base sequences) in a DNA
or RNA molecule or the order of amino acids in a protein.
Sex chromosomes (X and Y chromosomes) – chromosomes that are involved in
sex determination. In humans, XX corresponds to female and XY to males. In STR
testing, typed at the amelogenin locus.
STR (short tandem repeats) – in DNA testing, a subset of polymorphic VNTR loci
where alleles differ primarily in the number of times that a string of four
nucleotides are tandemly repeated.
Southern blotting – transfer by absorption of DNA fragments separated in
electrophoretic gels to membrane filters for detection of specific base sequences by
raiolabeled complementary probes.
Stutter – PCR amplification products that are one or more repeat units less (or
more) in size than a sample’s true allele and arise during PCR because of strand
slippage. Typically 15% or less of the height of the true allele.
Tandem repeat sequences – multiple copies of the same base sequence on a
chromosome; used as a marker in physical mapping.
profiling, it is the probability that the DNA of a randomly chosen person has a
DNA profile that cannot be distinguished from that observed in an evidence
sample.
Recombinant DNA technologies – procedures used to join together DNA
sequences in a cell-free system. Under appropriate conditions, a recombinant DNA
molecule can enter a cell and replicate there, either autonomously or after it has
become integrated into a cellular chromosome.
Resolution – degree of molecular detail on a physical map of DNA.
Restriction enzyme – a protein that recognizes specific, short nucleotide sequences
and cuts DNA at those sites. Bacteria contain over 400 such enzymes that
recognize and cut over 100 DNA sequences.
Restriction fragment length polymorphism (RFLP) – variation between
individuals in DNA fragment sizes cut by specific restriction enzymes;
polymorphic sequences that result in RFLPs that are used as markers on both
physical maps and genetic linkage maps. RFLPs are usually caused by mutation at
a cutting site.
RFU (relative fluorescent units) – units of measure for the light intensity detected
by a fluorescence detector, correlated with the amount of DNA associated with a
particular STR allele.
Serology – a discipline that uses immunology to study body fluids.
Sequencing – determination of the order of nucleotides (base sequences) in a DNA
or RNA molecule or the order of amino acids in a protein.
Sex chromosomes (X and Y chromosomes) – chromosomes that are involved in
sex determination. In humans, XX corresponds to female and XY to males. In STR
testing, typed at the amelogenin locus.
STR (short tandem repeats) – in DNA testing, a subset of polymorphic VNTR loci
where alleles differ primarily in the number of times that a string of four
nucleotides are tandemly repeated.
Southern blotting – transfer by absorption of DNA fragments separated in
electrophoretic gels to membrane filters for detection of specific base sequences by
raiolabeled complementary probes.
Stutter – PCR amplification products that are one or more repeat units less (or
more) in size than a sample’s true allele and arise during PCR because of strand
slippage. Typically 15% or less of the height of the true allele.
Tandem repeat sequences – multiple copies of the same base sequence on a
chromosome; used as a marker in physical mapping.
Taq polymerase
Taq polymerase – a DNA polymerase (an enzyme) used to amplify a specific DNA
template in the PCR technique.
VNTR (variable number of tandem repeats) – in DNA testing, a polymorphic
locus where alleles differ primarily in the number of times that a string of
nucleotides are tandemly repeated. Widely used throughout the 1990’s but largely
replaced by PCR-based STR testing today.
template in the PCR technique.
VNTR (variable number of tandem repeats) – in DNA testing, a polymorphic
locus where alleles differ primarily in the number of times that a string of
nucleotides are tandemly repeated. Widely used throughout the 1990’s but largely
replaced by PCR-based STR testing today.
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