allele
an alternate form of a gene; for example, a gene for human hair color may have these that cause red or brown hair
chromosome
a cell structure that contains genetic information along strands of DNA
DNA fingerprint
pattern of DNA fragments obtained by examining a person's unique sequence of DNA base pairs (also called DNA profiling)
DNA probe
a molecule labeled with a radioactive isotope, dye, or enzyme that is used to locate a particular sequence or gene on a DNA molecule
electrophoresis
a method of separating molecules, such as DNA, according to their size and electrical charge using an electric current passed through a gel containing the samples
gene
segment of DNA in a chromosome that contains information used to produce a protein of an RNA molecule
PCR
(polymerase chain reaction) a method used to rapidly make multiple copies of a specific segment of DNA; can be used to make millions of copies of DNA from a very small amount of DNA
restriction enzyme
a molecule that cuts a DNA molecule at a specific, base sequence
STR
(short tandem repeat) tandem (next to each other) repeats of short DNA sequences (two to five base pairs) with varying numbers of repeats found among individuals
VNTR
(variable number of tandem repeats) tandem repeats of a short DNA sequence (9 to 80 base pairs) with varying numbers of repeats among individuals
DNA extraction
first step in preparing a sample for DNA fingerprinting
primer
part of a gun cartridge that produces the spark to ignite the gunpowder
What are the components of DNA?
DNA is made up of deoxyribose, phosphate groups, and nitrogenous bases
Whats the difference between DNA found in two unrelated individuals, two related individuals, and identical twins?
DNA is unique to all persons except in identical twins, related individuals will have some DNA in common
What is meant by the human genome and the number of genes found in the human genome?
the human genome is the total amount of DNA in chromosomes and mitochondria
What percentage of DNA consists of the coding portion of DNA and what percentage of your DNA consists of the non-coding DNA?
1.5% is coding and the other 98.5% is noncoding DNA
What are 4 different sources of DNA that can be collected from a suspect?
skin cells, blood, saliva, semen, hair
Why is DNA evidence considered to be individual evidence?
DNA is unique to every person so it is capable of identifying a specific person
How is DNA extracted from cells?
cells are isolated from tissue and are then disrupted to release the DNA from the nuclear and cell membrane as well as from proteins and other cell components
How can trace DNA evidence by amplified using PCR reactions?
it copies the DNA billions of times
How are restriction enzymes used in DNA fingerprinting?
they cut the DNA, creating fragments of different lengths
where do you find VNTRs?
they are in the noncoding sections of DNA
What size are VNTRs?
9-80 base pairs
How many repeats are possible for VNTRs?
the number of repeats varies from one person to another
what is the role of VNTRs in electrophoresis?
in some VNTR analyses, DNA is cut by restriction enzymes while in other cases the VNTR specifically chosen DNA fragments are amplified using PCR
Whats the difference between VNTRs and STRs in regard to number of base pairs?
STR is much shorter, usually only 2 to 5 base pairs in length
How are radioactive probes used in DNA fingerprinting?
they help to identify specific DNA sequences
How do you use DNA fingerprinting to identify DNA from a parent, child, or relative of another person?
a child inherits two genes from each trait--one gene from the mother and one gene from the father. If the two genes from the parents are different, then two bands will appear in the child's DNA fingerprint but if the two genes are the same then only one b
What is the function of the mitochondria?
the mitochondria is the power house of the cell, house the ATP
Compare and contrast the location and source of mitochondria DNA to nuclear DNA
mDNA comes from the mother and is easier to extract than nuclear DNA. It is also less likely to degrade and is typically extracted from teeth, hair, and bones
What are the two types of DNA extractions?
chelax extraction--used when there is a small amount of evidence available
organic extraction--used when more evidence is available
What are the three steps of PCR?
denaturing, primer annealing, and polymerization