ALL about DNA
History. Dicovery. Technology by: Tatiana Williams
What is DNA?
Deoxyribonucleic Acid can be found in two important places, the nucleus and the mitochondria.
DNA is a code that divided up into gene sections that ensure instructions for making up the body are being carried out.( Also made up of Nucleotides)
In side of a cell there is a nucleus which contains chromosomes; these chromosomes inside of the nucleus are made up of DNA
DNA is also Hereditary
The structure of DNA is called a double helix( looks as if two strands are twisting around each other coiled tightly) , it is created by a process of base pairing
Base pairing is system in which Adenine and Thymine pair, Guanine and Cytosine pair in order to create this double helix structure
DNA replication happens usually in the cytoplasm of prokaryotes and in the nucleus for eukaryotes.
1. DNA gyrase an enzyme makes a slit in the double helix and then both side split
2. Another enzyme named helicase untangles the DNA strands
3. Single strand binding proteins keep them separated using temporary binding
4. DNA polymerase then adds new Nucleotides to each strand(A,T,G,C)
5. Another unit of DNA the reviews the new DNA
6. A DNA enzyme called ligase closes up fragments into one long strand
7. New copies then coil up again automatically
DNA TECHNOLOGY TIMELINE (1928-Present)
1949-CHARGAFF , discovery of adenine and thymine being the percentage as well as Cytosine and Guanine.
1952-Wilkins and Franklin, took the first x-ray of the double helix structure (discovered the structure).
1953- Watson and Crick , created the first model of DNA using the double helix structure.
1980- Watson and White , explained the polymorphic RFLP marker
1991- Orginal STR paper
1985- Alec Jeffery separated DNA markers and identified them as Fingerprints. Kary Mullins had also created PCR testing.
1988- FBI using DNA as case work and launches a CODIS database
1990- First DNA evidence presented in court
1995- National DNA databank established
2001- Cold case by Theresea Cormack was solved using DNA
2002- Forensic DNA labs are built nationally
2005-Robots presented to DNA lab
2006- Y-STR introduced
2008- New extraction technology used
2009-Now)- Idvidual profiles are added to databank
PCR . STR . Gel Electrophoresis.
STR-(Short Tandem Repeats) Because DNA has a lot to deal with heredity this helped create paternity tests but this also refers to the sequences of DNA like GATA or TAGA
Gel Electrophoresis- Helps analyze and separate DNA and RNA and Proteins based on charge and size.
Nuclear VS. Mitochondrial DNA
Nuclear DNA's genes get rearranged in when they are recombining , in mitochondrial DNA the genes are not changed they are given from the parents sent to the offspring. Because there is no change its more likely that a mutation can be cause from Mitochondrial DNA. DNA found in the Mitochondria is good to used for ancestor tracing. MtDNA can also be used to identify individuals.