8B- Genetic Fingerprinting Flashcards
Genomes contain non-coding variable number tandem repeats
Not all of an organism’s genome codes for proteins.
Some genomes consist of variable number tandem repeats (VNTRs)- base sequences that don’t code for proteins and repeat over and over.
The number of times it differed depends on person to person, so the length differs too.
It occurs in lots of places in the genome. The repeats can be compared between individuals- genetic fingerprinting.
How does electrophoresis separate DNA fragments to make a genetic fingerprint?
A sample of DNA is obtained.
PCR is used to replicate the DNA that contains the VNTRs.
You end up with DNA fragments where the length corresponds to the number of repeats.
A flourescent tag is added so it can be seen under UV light.
The DNA mixture is placed into a well in a slab of gel and covered in a buffer solution that conducts electricity.
An electrical current is passed through the gel- DNA fragments are -vely charged so move tested the +ve electrode at the far end.
Small DNA fragments move faster and travel further through the gel, so the DNA fragments separate according to size.
The DNA fragments are viewed as bands under UV light.
The results can be compared to see a match.
How is genetic fingerprinting used to determine relationships and variability?
Determining genetic relationships-
We inherit VTNR base sequences from our parents. This means the more bands on a genetic fingerprint that match, the more closely related.
Determining genetic variability within a population-
The greater the number of bands that don’t match, the more genetically different. This means you compare the number of repeats to find out how genetically varied the population is. The more the number of repeats varies at several places, the greater the genetic variability within a population.
How can genetic fingerprinting be used in forensic science?
Can compare DNA found at crime scenes to samples of DNA from possible suspects.
The DNA is isolated from all the collected samples.
Each sample is replicated using PCR.
The PCR products are run in an electrophoresis gel and the genetic fingerprints produced are compared to see if any match.
If they match, it links a person to a crime scene.
Genetic fingerprinting can be used in medical diagnosis?
A genetic fingerprint can refer to a unique pattern of several alleles.
It can be used to diagnose genetic disorders and cancer. It is useful when specific mutation isn’t known or where several mutations could have caused the disorder, because it identifies a broader, altered genetic pattern.
For example, it can identify a cystic fibrosis gene in an embryo.
How can genetic fingerprinting be used in animal and plant breeding?
It can be used to prevent inbreeding, which decreases the gene pool.
Inbreeding can lead to an increased risk of genetic disorders, leading to health and reproductive problems.
It can be used to identify how closely related Indic are, the least related will breed together.
