DNA test
What is PCR? How many thermal cycles does it take to get 2 copies of the targeted DNA sequence? 22 copies? 1 billion copies?
Polymerase chain reaction; process that amplifies DNA; makes 1 billion copies of a specific fragment of DNA after 30 cycles
Explain how gel electrophoresis works. What charge does DNA have?
Process that separates DNA fragments by length DNA is negative charge
What is the base pairing rule?
A - T and C - G
11. How should biological evidence be collected, packaged and preserved at a crime scene?
Air tight plastic containers
How many base pairs are there in the human genome? How much of your DNA is coding DNA? How much of your DNA is the same as everyone else's?
Approximately 3 billion 5% coding DNA 95% non-coding DNA 99.4% of your DNA is identical to everyone else's
Name at least 5 sources of DNA at a crime scene.
Blood (WBC's) Saliva - stamps, envelopes, straw, glass, gun Semen - sexual offenses, (sperm head) Hair - if follicle, shaft mtDNA Bone Marrow - retains DNA for years
. What is the lysis solution used for in DNA extraction? The alcohol?
Breaks open cells Precipitates DNA
What is the difference between a genome, a chromosome, a gene and an allele?
Chromosome - cell structure that contains genetic information along strands of DNA Gene - segments of DNA on a chromosome that contain information used to produce a protein Allele - an alternate form of a gene
Explain the difference between a chromosome, a gene and an allele. How many chromosomes are in each body cell? In each sex cell?
Chromosome - cell structure that contains genetic information along strands of DNA Gene - segments of DNA on a chromosome that contain information used to produce a protein Allele - an alternate form of a gene 23 pairs, 46 total, chromosomes in each cell Sex cells have 23 total each
What is CODIS and how is it used? How many loci are tested?
Combined DNA Index System; database of DNA profiles kept by FBI; uses 13 loci to fingerprint DNA
What is allele frequency and why is it important?
Frequency of alleles at a certain locus, fraction of all chromosomes that carry an allele
Give at least 4 reasons for DNA testing.
Investigate crimes (link or exclude a suspect) Establish paternity Identify victims of war or mass disasters
. How many alleles are at each locus on a chromosome?
two
