DNA
Abbreviation for deoxyribonucleic acid - the molecules carrying the body's genetic information. ___ is double stranded in the shape of a double helix.
Chromosome
A rodlike structure in the cell nucleus, along which the genes are located. It is composed of DNA surrounded by other material, mainly proteins.
Polymer
A substance composed of a large number of atoms. These atoms are usually arranged in repeating units, or monomers.
Nucleotide
The unit of DNA consisting of one of four bases - adenine, guanine, cytosine, or thymine - attached to a phosphate-sugar group.
Complimentary Base Pairing
The specific pairing of base A with T and base C with G in double-stranded DNA.
A
Base T
C
Base G
A
Adenine
G
Guanine
C
Cytosine
T
Thymine
Proteins
Polymers of amino acids that play basic roles in the structures and functions of living things.
Amino Acids
The building blocks of proteins. There are twenty common amino acids. Amino acids are linked to form a protein. The types of amino acids and the order in which they're linked determine the character of each protein.
Human Genome
The total DNA content found within the nucleus of a cell. In humans, it is composed of approximately three billion base pairs of genetic information.
Replication
The synthesis of new DNA from existing DNA.
Polymerase Chain Reaction (PCR)
A technique for replicating or copying a portion of a DNA strand outside a living cell. This technique leads to millions of copies of the DNA strand.
PCR
Polymerase Chain Reaction - A technique for replicating or copying a portion of a DNA strand outside a living cell. This technique leads to millions of copies of the DNA strand.
Restriction Enzymes
Chemicals that act as scissors to cut DNA molecules at specific locations.
Restriction Fragment Length Polymorphisms (RFLP)
Different fragment lengths of base pairs that result from cutting a DNA molecule with restriction enzymes.
RFLP
Restriction Fragment Length Polymorphisms - Different fragment lengths of base pairs that result from cutting a DNA molecule with restriction enzymes.
Electrophoresis
A technique for separating molecules through their migration on a support medium while under the influence of an electrical potential.
Hybridization
The process of joining two complementary strands of DNA to form a double-stranded molecule.
Primer
A short strand of DNA used to target a region of DNA for replication by PCR.
Short Tandem Repeat (STR)
A region of a DNA molecule that contains short segments consisting of three to seven repeating base pairs.
STR
Short Tandem Repeat - A region of a DNA molecule that contains short segments consisting of three to seven repeating base pairs.
Multiplexing
A technique that simultaneously detects more than one DNA marker in a single analysis.
Amelogenin Gene
A genetic locus useful for determining gender.
Y-STRs
Short tandem repeats located on the human Y chromosome. Their utility in forensic science is that they originate only from a male donor of DNA.
Mitochondria
Small structures located outside the nucleus of a cell. These structures supply energy to the cell. Maternally inherited DNA is found in each mitochondron.
Sequencing
A procedure used to determine the order of the base pairs that constitute DNA.
Picogram
One-trillionth of a gram, or 0.000000000001 gram.
Low Copy Number
Fewer than eighteen DNA-bearing cells. Less than 100 picogram of DNA.
Epithelial Cells
The outer layer of skin cells. These DNA-bearing cells often fall off or are rubbed off onto objects retrieved from crime scenes.
Substrate Control
An unstained object adjacent to an area on which biological material has been deposited.
Buccal Cells
Cells derived from the inner cheek lining.
gene
The fundamental unit of heredity is the _________.
polymer
A(n) ____________ is a very large molecule made by linking a series of repeating units.
nucleotides
DNA is actually a very large molecule made by linking a series of _____________ to form a natural polymer.
double helix
Watson and Crick demonstrated that DNA is composed of two strands coiled into the shape of a(n) ____________.
A-C-G-T
The base sequence T-G-C-A can be paired with the base sequence _____________ in a double-helix configuration.
Proteins
_____________ are derived from a combination of up to twenty known amino acids.
TRUE
True or False. Enzymes known as DNA polymerase assemble new DNA strands into a proper base sequence during replication.
restriction enzymes
Recombinant DNA relies on the ability of chemicals known as ________.
repeating
In RFLP DNA typing, restriction enzymes are used to cut out (repeating, random) sequences from the DNA molecule.
electrophoresis
DNA fragments can be sorted according to their size by the technique of ____________.
TRUE
True or False. In the RFLP DNA typing process, a radioactively labeled probe is used to visualize the separated DNA fragments.
Two
IN RFLP DNA typing, a typical DNA pattern shows (two, three) bands.
STRs
Short DNA segments containing repeasting sequences of three to seven bases are called _______________.
PCR
The short length of STRs allows them to be replicated by __________.
capillary electrophoresis
DNA fragments can be separated and identified by (gas chromatography, capillary electrophoresis).
male
Y-STR typing is useful when one is confronted with a DNA mixture containing more than one (male, female) contributor.
TRUE
True or False. Mitochondrail DNA is more plentiful in the human cell than is nuclear DNA.
FALSE
True or False. Polymerase chain reaction is a part of the process used in the forensic alaysis of RFLP, STRs, and mitochondrial DNA.
FALSE
True or False. Y-STR data is normally entered into the CODIS database collection.
FALSE
True or False. Airtight packages make the best containers for blood-containing evidence.
two
A typical STR DNA type emanating from a single individual show a (one, two, three) - band pattern.
DNA
Each gene is actually composed of ___________, specifically designed to carry out a single body function.
nucleotide
A(n) ___________ is composed of a sugar molecule, a phosphorus-containing group, and a nitrogen-containing molecule called a base.
Four
________________ different bases are associated with the makeup of DNA.
T, C
The structure of DNA requires the pairing of a base A to _______ and base G to _______.
proteins
The inheritable traits that are controlled by DNA arise out of DNA's ability to direct the production of ___________.
three
The production of amino acid is controlled by a sequence of ____________ bases on the DNA molecule.
TRUE
True or False. DNA can be copied outside the living cell.
FALSE
True or False. All of the letter sequences in DNA code for the code for the production of proteins.
lengths
In RFLP DNA typing, restriction enzymes are used to cut out sequences of DNA with different (widths, lengths).
Southern
In the RFLP DNA typing process, DNA fragments are transferred to a nylon membrane by a process called ___________ blotting.
A-T-C
The probe complementary to the base sequence T-A-G has the letter sequence _____________.
FALSE
True or False. The longer the DNA strand, the less susceptible it is to degradation.
multiplexing
The concept of (CODIS, multiplexing) involves simultaneous detection of more than one DNA marker.
male, female
The amelogenin gene shows two bands for a (male, female) and one band for a (male, female).
mother
Mitochondrial DNA is inherited from the (mother, father).
Two
(Two, Four) regions of mitochondrial DNA have been found to be highly variable in human population.
thirteen
The National DNA database in the United States has standardized on ___________ STRs for entry into the database.
dry
Small amounts of blood are best submitted to a crime laboratory in a (wet, dry) condition.
EDTA (ethylenediamine tetraacetic acid)
Whole blood collected for DNA typing purposes must be placed in a vacuum containing the preservative ______________.
red blood
All but ___________ cells contain a nucleus where genetic information is stored.
Gene
A hereditary unit found on a chromosome. About 20,000 to 30,000 genes in human cell
Allele
A particular form of a gene inherited from one parent.
23
________ pairs of chromosomes that result in a total of 46 total chromosomes in human cells.
Females, males
_________ have 2 X sex chromosomes while _______ have a X and Y sex chromosome.
Genotype
_________ is the genetic makeup of a trait (the combination of alleles, or genes, from each parent).
Phenotype
___________ is the physical representation of the genotype (the way a trait looks).
Homozygote
____________ is the condition of inheriting the same allele of a gene from both parents (WW or ww).
Heterozygote
_________ is the condition of inheriting 2 different alleles of a gene from each parent (Ww).
Missing
Human Identity Testing is use for Forensic cases, Paternity testing, Historical investigations, ________ persons investigations, Mass disasters, Military DNA, Convicted felon DNA databases.
CODIS
1998 - FBI launches _________ database.
Tandom, number, profiling
VNTR: Variable-Number _______ Repeats. Genotype is defined by a particular _______ of tandem repeats at a given locus. VNTR __________ utilizes RFLP
Locus (loci), marker
__________ referes to the location of a gene or genetic __________ on chromosomes.
Amplified, STR
AFLP: ________ Fragment Length Polymorphism. Requires less DNA and better with degraded samples. Replaced with ________ system in 1990's.
2-6 bp
Length of STR repeat can be _______ (base pair) long.
Dr. Kary Mullis
Polymerase Chain Reaction (PCR) developed in 1984 by _________ who won Nobel Prize.
father, male
Y Chromosomes are inherited from the ________. Unique to males. Contain _________-specific function.
PAR
Psudo-Autosomal Region(_______) is a recombination with homologous regions on the X chromosome during meiosis.
MSY
Male Specific Y Region.
one, two, less
A Y-STR analysis will have only ______ band or peak, rather than the conventional STR which is derived from two chromosomes and has ________ bands or peaks. Making the Y-STR ______ complicated.
haplotype, linked
Y-STRs are usually referred to as ________ or a collection of alleles that are _________ (inherited together).
nine
European Minimal Haplotype (EMH) contains _________ core sets of loci.
eleven
U.S. Haplotype contains ________ core sets of loci.
First, largest
National DNA Database (NDNAD), UK, was Worlds __________ and contains __________ number of profiles in proportion to populations.
Local, State, National
US' Combined DNA Index System (CODIS) contains databases from _______ DNA Index (LDIS, ______ DNA Index (SDIS), and ________ DNA Index (NDIS)
Robust
________ produces accurate results a high percentage of the time.
Reliable
_______ produces accurate results that reflect the samples tested.
reproducible
__________ achieves the same or very similar results each time a sample is tested.