forensic molecular biology exam 1

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