DNA Flashcards
What are DNA markers
Sequences of DNA used to identify individual people of characteristics of human populations
DNA is used in tracking migration of people
A marker might spread through a human group after it has branched off from other human groups
markers and disease susceptibility
DNA markers can be within or close to disease gene and can signal the presence of those disease genes in someones genome
DNA is what kind of structure
Polymer
large molecule built from other sub units
What are DNA monomers called?
Nucliotides
A,T,C,G
when you hook nucliotides together you can make what?
Polynucliotides
sugar-phosphate backbone with a 5’ and 3’ end
sequencing is what?
Complementary
why is it helical?
Mot stable (low energy) state
what is the polyelectrolyte theory?
Negative chages on the two backbones of the DNA spread it out, giving easier access to the machinery that reads and copies the base sequence
some DNA embodies genetic information and some?
Does not
How is DNA copied?
DNA polymerization reactions which are catalized my enzymes
what is the enzyme responsible for DNA replication?
DNA polymerase
what is Ethidum bromide?
A flat fluorescent molequle that can slide between the stacked base pairs of DNA
- helps visualize DNA
Seperation of DNA
A carb from seaweed, agarose, when mixed with water, heated, and cooled, will form jelly-like substance that is full of tiny holes
when current is applied to solution containing DNA the DNA will be drawn to the positive pole due to its negative charge
ITS CALLED ELECTROPHORISIS
How can DNA sequences be amplified for detection
Polymerase chain reaction (PCR)
depends on the DNA replication reactions which in turn depends on the phenomenon of specific base pairing
What you need for PCR
DNA template
short DNA primers with sequences that flank the sequence you want to amplify
free ucleotides
Taq polymerase- a DNA polymerase from a heat resistant bacterium that can be heated without being dystroyed
a thermal cycler
What do genes do
Code for proteins
what does a chromosome do?
Have 100s to 1000s of genes
DNA does what? Proteins do what?
DNA hold genetic info
proteins help pack it
the genome is what?
All of its genes collectively
A typical cell has two versions of each gene the versions are called what?
Alleles
Homologous chromosomes or homologuse
How are chromosomes and their genes inherited?
Meiosis- reductual division of the daughter cell
What does the Y chromosome do?
Determines maleness in people is passed only from father to son
A polymorphism is a what?
location on a specific chromosome that has appreciable variation in a population
What is a single nucleotide polymorphisms (SNPs)
A signle nucleotide polymorphism is asite where different base pairs are found in different individuals the site might be part of a gene or might be outside gene sequences
what are two other useful types of polymorphism?
variable number of tandem repeats (VNTRs) and Short tandem repeats (STRs)
VNTR regions are sites in the genome where what?
DNA sequence (15-100 base pairs long) is repeated over a distance of 1000-20000 base pairs
A STR is what?
A region 2-9 base pairs and repeated 7-40 times
DNA fingerprinting
what are the sources of DNA
Hair semen blood bits of tissue saliva bone
if lots of tissue and DNA is avalible what type of Polymorphisms?
VNTRs
if small amounts of tissue and DNA is avalible what type of Polymorphisms?
STRs
how can you calculate the probability of a DNA match between two unrelated people?
The hardy-weinberg equilibrium
What can go wrong with DNA evidence?
It can be too degraded to use
contaminating DNA was introduced
planted of fabricated DNA
two experts draw different conclusions from the same evidence
What is the prosecutors fallacy?
Unwise practice of not looking at other kinds of evidence in the case which might nullify the probability calculation
First case of DNA evidence
Pitchfork case
Roy brown case
Example of DNA evidence trumping over other kinds of evidence
Migration of human populations
Some groups of people are isolated for long enough that specific variant DNA sequences become common in the population
nesting effect when one group gives rise to another group
supporsts the Out-of Africa model of human evolution and migration
DNA markers can determine ancesty how?
Because specific markers are found in specific human groups, analysis of our DNA can tell you some thing
the most frequently used marker is the Y chromosome and the mitochondrial genome
Genomics and personalized medicine
Some diseases with a genetic component have been studies at the level of the gene and this knowledge can help diagnose and treat
(Huntinngton disease)
What is the DNA barcode project?
An attempt to derive a set of unique markers for wild animal and plant species
can be used to fight illegal trade in endangered organisms
when were the first dogs domesticated?
Central aisa 15000 years ago
