For discussing the functions of different structures of all organisms.
Yeah, you basically look for repeating sequences of DNA in the "junk DNA"... These regions of tandemly repeated sequences are called "satellite regions"... you also get smaller repeat regions called "minisatellite" and "microsatellites" regions...
Yes of course... Scientists have got DNA from bones from animals hundreds of thousand of years old...
You can use a technique called PCR which can replicate the quantity of DNA from a very very very very small source of DNA... You basically heat the DNA, add primer, cool to allow DNA polymerase to work on the strand... that doubles quantity of DNA... you repeat heating and cooling cycles until you have enough DNA for genetic analysis...
If there was no root present you could not PCR the DNA. I have heard that you can obtain mitochondrial DNA from a hair shaft, but i don't know the protocol.
There are other ways of analysing DNA for identification purposes other than tandem repeats although they are not as definitive..
For example, Restriction fragment length polymorphisms.
These are short pallandromic sequences dotted around the gene. Enzymes target these sequences and cut the DNA strand at these points. This leaves the DNA in fragments of various sizes depending on how many of these pallandromic sequences you have.
So when you PCR the gene, how far down the gel it goes will tell you the size of the frangments you have created.
It can used for DNA testing as it contain mitochondrial DNA. Coincidently i've blogged bout hair DNA via http://dnamazing.com/hair-styles-and-dna-testing/
DNAmazing - http://dnamazing.com - Provides Myriad Information About Cutting-edge of DNA Testing & Genealogy
OK guys...here you go:
Nuclear DNA can be extracted from hairs as long as they contain the root. The root is the portion of the hair that contains actual living cells which, in turn, contain nDNA.
There are many different extraction protocols to extract DNA, mainly proteinase K, NaOH, ethanol precipitaion, orgainc extraction, etc. Once the DNA is extracted, it is purified using a Microcon 100 concentrator or QIAGEN before it is amplified by PCR. After amplification, genetic analysis can be performed utilizing a number of commercial kits (ex. Identifiler, MiniFiler, etc) that detect alleles at specific markers (known as STRs) to obatin a genetic profile of the individual from which the hair was collected.
Alternatively, when a hair is naturally shed, it does not usually contain the hair root. It is just the shaft of the hair. This means that there are NO living cells present, thus, nuclear DNA CANNOT be extracted and analyzed. However, every cell contains mitochondira which provide energy. Mitochondrial cells contain their own type of DNA called mtDNA. Contrasting from nuclear DNA that is a double-helix, mtDNA is circular. It is very compact and has a coding region and a non-coding region.
Everything is performed the same for DNA extraction, purification, and PCR amplification, but analysis is completely different. Instead of mapping the alleles present at certain loci, the non-coding region of mtDNA contains two hypervariable regions (HV1 and HV2) that are prone to polymorphisms or variation. It is the sequencing of these two regions compared to what is termed as the revised Cambridge Reference Sequence that yeilds mtDNA analysis. mtDNA, however, CANNOT differentiate between two individuals like nuclear DNA can. mtDNA is passed down genetically through maternal lineage, so relatives who share a common female individual will have identical mtDNA. This presents a problem since male to male comparisons CANNOT be made through mtDNA analysis. For example, if you have a son and you want to test 2 individuals for paternity, mtDNA analysis will NOT help you in ANY way.
Also, mtDNA is far better preserved in cells than nuclear DNA so a lock of hair that is 5 years old should have no problem extracting mtDNA. In fact, there have been publications of extracting mtDNA from wholly mammoth hair!!
Just a quick reaction to this:
There is a big error here. genomic DNA and mtDNA both form a double helix: but gDNA is linear, while mtDNA is circular. And the DNA is chemically the same, the difference is the location in the cell.
Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)
And I don't like "mitochondrial cells"...
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter
OK so let's say this is the case.
I have 2 Years old hair from the woman that gave birth to a female baby which could also be my child, so now the question is, can I make Paternity and Maternity test by Using my hair and mother's hair and Kids hair???
all the hairs don't have the root which means I just CUT some hair from the woman and I still have it but it is 2 years old, so now if I cut hair from the Child without the root and take it for Analysis will they be able to tell from the hair that has been CUT if I am her father or not.
I will ask for my Ex to cut some hair from the Kid and send it to me and then I will send Mother's hair and her hair for analysis just in case to see if she is trying to deceive me with someone else's hair and then when they confirm that the Hair I have from the Mother and the Hair that she will send me from the kid match and she is her mother then I will make another Analysis by sending my hair or blood so they can see if the Female Kid is my Child.
is this possible??????
Please someone answer me this as soon as possible.
Thank you in Advance.
yes it is possible to use hair to identify somebody but only is the root is still attached on the hair as this is the part that contains a person's unique DNA.
Other examinations can also be used if the DNA is substandard due to degradation such as pigmentation, morphology such as the medulla and tip characteristics, chemical treatments, race of the donor etc. these can be used to match the hair to an individual although this isn't as solid as DNA of course.
In cases of paternity the DNA from the root of the hair is analysed focusing on the Y chromosome.
_at_ sdekivit the methods of DNA profiling in forensics (in the UK) these days usually relies on STR loci using the SGM+ system as STR loci are highly variable and this method has a statistical power of discrimation.
BSc (Hons) Forensic Science
BSc (Hons) Forensic Science,
MSc Biological Sciences
If there is no root and the hair is that old then it is unlikely that vible DNA will be able to be extracted from it.
There will still be mtDNA present but this obviously will only infer materal lineage and not paternity.
There is a way round this I think though if you explained your situation to a paternity testing company.
They should be able to say that the hair you have is the mothers hair from typing the mtDNA and comparing it to that of the child.
Although you mention "cutting"? you would be better off plucking at least 5 hairs which contain roots from your own head for analysis and then also getting the same amount of plucked hair (with roots) from the child......this way a paternity test can be carried out using DNA to see if the child is yours or not.
Hope this helps
BSc (Hons) Forensic Science,
MSc Biological Sciences
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