law enforcement, scientific analysis, legal proceeding
the three components of the criminal justice system
1986
when was DNA first used to solve a crime?
the innocence project
an organization staffed by lawyers and law students who reexamine cases using post-conviction DNA testing to possibly exonerate wrongly accused suspects
identical twins
the exception to every individual having a unique genome
false
true or false: DNA testing looks at genes
biology, technology, genetics
the three steps in DNA sample processing
reference sample
required for DNA testing to be able to identify a suspect
DNA
an essential component of all living matter and a basic material in the chromosomes of the cell nucleus, containing all the genetic code and hereditary pattern
make copies of itself
the purpose of DNA is to ________ and carry instructions on how to make proteins
Deoxyribo Nucleic Acid
DNA stands for...
nucleotides
nucleic acids are composed of _________
sugar, nitrogen base, phosphate
the three components of a nucleotide
ribose
the sugar in RNA
deoxyribose
the sugar in DNA
carbon 1 of sugar
nitrogenous bases form a bond with ....
2
purines have ____ ring(s)
adenine and guanine
the two purine bases
1
pyrimidines have ____ ring(s)
cytosine, thymine, uracil
the three pyrimidine bases
double helix
the secondary structure of DNA
hydrogen bonds
the two chains of DNA are held together with ....
anti-parallel
the two strands of DNA are _______, meaning the run in opposite directions
nucleosomes
the basic subunit of chromatin, consisting of 200 bp of DNA wrapped around an octamer of histone proteins
chromatin
the complex of DNA and proteins in the nucleus of a cell in interphase
histones
DNA binding proteins that help compact and fold DNA into chromosomes
genes
segments of DNA molecules that control the production of different proteins in an organism
genome
all of the genetic material in an organism
exon
segment of a gene that is represented in the final mRNA product and expressed as a protein
introns
non-coding DNA which separates neighboring exons in a gene
introns
do we look at introns or exxons in forensics?
transcription
begins when RNA polymerase binds to the promoter region of a strand of DNA and adds complementary ribonucleotides to a chain, creating a single stranded RNA
codon
the three nucleotide sequence on mRNA
amino acid
each codon on mRNA codes for a(n)...
ribosomes
translation occurs on the _______
anticodon
the nucleotide triplet at on end of the tRNA that is complementary to a mRNA codon
hybridization
the binding or reassociation of complementary strands of nucleic acids
locus
the chromosomal position or location of a gene sequence
sequence polymorphism
a type of polymorphism where one or more nucleotides vary within a sequence or length of DNA
length polymorphism
a type of polymorphism where the sequence of the DNA doesn't vary, but the number of times it's repeated does
power of discrimination
the ability of a forensic DNA technique to discern the difference between individuals
genetics
the study of the pattern of inheritance
populations
groups of individuals residing in a given area at a given time, often sharing a common ancestry
population genetics
the study of genetic diversity in populations and how it changes over time
law of segregation
states that chromosome pairs separate during meiosis so that sex cells are only haploid and possess a single copy of each chromosome
law of independent assortment
states that different segregating gene pairs behave independently of one another due to recombination
recombination
the process of exchanging DNA between homologous chromosomes that occurs during meiosis
linkage
the proximity of two or more markers on a chromosome; the closer they are together, the more likely they are to be inherited together
linkage equilibrium
the condition among alleles at different loci such that any allele combination in a gamete occurs as the product of the frequencies of each allele at its own locus
linkage disequilibrium
the condition among alleles at different loci such that any allelic combination in a gamete do not occur according to the product rule of probabilty
restriction fragment length polymorphism
RFLP stands for...
variable number tandem repeat
VNTR stands for...
RFLP
an analysis where DNA fragments are separated by their length using gel electrophoresis
nuclease
an enzyme that degrades nucleic acids and DNA
micrococcal
type of nuclease that can only cleave DNA that is not protected by proteins. ex.) linker DNA between histones
endonuclease
type of nuclease that can only cleave DNA within a chain
exonuclease
type of nuclease that can only cleave DNA on the end of a chain
restriction endonucleases
restriction enzymes are also called...
restriction enzyme
recognizes specific DNA sequences and cleaves both strands of DNA at sites internal to the molecule
palindromes
restriction enzymes recognize _________, or sequences that are the same on both antiparallel strands of DNA
restriction site
the actual bonds within the recognition site that get cleaved by the restriction enzyme
recognition site
the specific 4-8 bp sequence that a restriction enzyme recognizes
blunt ends
DNA that has been cleaved in a double stranded manner at the cut site
sticky ends
DNA that has been cleaves with one or more unbound nucleotides at the cut site
digestion
cutting high molecular weight DNA with a restriction enzyme
partial digest
when the restriction enzyme cuts DNA at some sites, but not all of the sites it's supposed to cut
electrophoresis
separating DNA or proteins based upon size using an electric current
southern blot
the transfer of DNA from an agarose gel to a nylon membrane
denaturation
the process of separating complementary strands of the double helix into two single strands
probe
short single stranded DNA sequence that is complementary to an area of DNA being examined
prehybridization
blocking areas of the membrane where DNA is not bound so that the probe will not bind to the membrane
stringency washes
washes away unbound probe and non-specifically bound probes, being struct with the hybrid that's permitted to form
recombinant dna
cutting up DNA molecules and splicing together fragments from more than one organism
transformation
the genetic alteration of a bacterial cell resulting from the transfer of foreign DNA
cloning vector
a plasmid or phage that is used to carry inserted foreign DNA for the purposes of producing more material or protein product
plasmid
a linear or circular double-stranded DNA that is capable of replicating independent of the chromosomal DNA
DNA ligase
an enzyme that facilitates the joining of DNA strands together by catalyzing the formation of a phosphodiester bond
polymarker DQ alpha
PM/DQA stands for...
reverse dot plot
when the probe is bound to the membrane and the sample DNA is washed over the membrane, rather than vice versa