DNA St. Patricks Day Salute to the Molecule of Heredity From Biology 110- UNC 1993 Steve Lee The molecular structure today Is heredity’s DNA With nucleotides completely comprised of a sugar and phosphate and base The bases you see are so keen They include thymine and adenine Cytosine and one more with guanine can store all the info with rungs in between The sides of the ladder you know, are sugar and phosphate which show that Franklin was right double helix is tight ten base pairs per turn in a row Adenine and thymine can base pair Forming two hydrogen bonds for one stair Cytosine and guanine pair with three in between and are equal in size when compared DNA strands are just not the same One is coding and one is called lame (anticoding) They are opposite in direction and this is called antiparallel in name Complimentary nature of strands lets replication proceed just as planned with A paring to T and G pairing to C the fidelity is precise and quite grand

Steps in Forensic DNA typing (Figure 6.1 Rudin and Inman 2001) Evaluation- Is it there? 1. Start with biological sample 2. Screen- blood? Semen? Saliva, human? Extraction- Get and clean DNA 3. Open cells  Get DNA 4. Methods to get DNA and purify DNA Quantify- Determine quality and quantity? 5. Quantify- How good and how much did you get? Type to determine and compare alleles 6. RFLP vs PCR 7. Determine alleles and compare DNA types Or alleles present in samples and references Interpretation of Results

Review: DNA is organized inside the cell nucleus and mitochondria

DNA Extraction After screening tests are performed, a spot of the material containing the biological sample is cut and placed into a tube. In one type of extraction method (organic), heat and chemicals are added, and protein is removed. Then the pure DNA is recovered by filtration in which the non-DNA material goes through a sieve. (analogous to a collection of your pasta in a colander)