CSI Wildlife (Gel Electrophoresis) Flashcards
How is DNA fingerprinting used to study elephants?
The results of the DNA fingerprinting is matched to the suspected elephant’s DNA.
How can the information obtained from DNA fingerprinting help save elephants?
Information from DNA fingerprinting reveals the individual elephant and its location, therefore certain measures can be increased in that area in order to reduce ivory poaching.
what does str stand for
short tandem repeats,string of nucleotide units that repeats
ex
GATA segment
GATAGATAGATAGATA
STRs at specific loci have shared characteristics between individuals and/or alleles. Highlight the characteristic(s) that are
shared.
Made up of nucleotides Flanking sequence unit, i.e., CTA
List three sources to obtain elephant DNA for analysis:
Hair roots, saliva, or body tissue
Why are flanking sequences important for amplifying STR fragments?
Flanking sequences are essential for amplifying STR fragments because it makes the enzymes initiate the copy process for STR fragments.
Scientists typically amplify multiple STR fragments from an individual in a single PCR. Explain how they can do that.
They use PCR to amplify STR fragments by using primers that are complementary to portions of the flanking sequences to make sure that the region in between are also amplified. This all leads to the amplification of multiple STR fragments in one PCR.
What is the relationship between the size of a DNA fragment and the distance it migrates in the gel?
The longer a DNA fragment, the farther it is from the end of the gel.
how do u know if an elephant is homozygous or heterozygous based on their gel
2 bands would= heterozygous
What do the bands represent?
DNA fragments that are versions of short tandem repeats (STR)
What is a DNA ladder used for? What are they measured in
- A DNA ladder is used as a reference for determining STR sizes.
- They are measured in base pairs (bp)
What is a DNA ladder?
A mixture of dna fragments of known lengths that allows you to work out the length of the bands in genetic fingerprints.
What is the flanking sequence?
The extension on either side of a specific gene
What does a marker represent?
A gene
What is allele frequency?
The number of times an allele occurs in a gene
1st step of dna profiling?
collect dna sample, any material containing cells
2nd step?
extract dna by chemicals, seperated from other cells components
3rd step?
amplify strr fragments
involves pcr (polyamerse chain reaction to make copies of <13 different STR regions,
using primers which flank the region binding on each side of the DNA.
TTTTTTTTTTT primers
⊥⊥⊥⊥⊥⊥⊥ <–template DNA
what is pcr
To amplify a segment of DNA using PCR, (1) denaturation of the template into single strands by heat; (2) annealing of primers to each original strand for new strand synthesis; and (3) extension of the new DNA strands from the primers.
4th sptep?
determine length of strs
seperated by gel electrophoresis
larger fragments, more str repeats, small fragments, less repeats
5th
interpret data
patterns of bands on the electrphohoh gel creates a DNA profile
whats gel electrophoresis
is a technique used to separate DNA fragments according to their size.DNA samples are loaded into wells (indentations) at one end of a gel, and an electric current is applied to pull them through the gel. DNA fragments are negatively charged, so they move towards the positive electrode.
