FSC239Y5 Chapter 15: DNA, The Indispensible Forensic Science Tool
Document Summary
Chapter 15: dna, the indispensable forensic science tool. Deoxyribonucleic acid: carries genetic information, double stranded helix, polymer. Chromosomes: rod-like structure, made of dna surrounded by other material. Gene: arranged on chromosomes, fundamental unit of heredity. A human cell contains two types of dna: nuclear dna, mitochondrial dna. All information in this section should have been covered in biology course. Useful in replicating small quantities of dna. Or broken pieces of dna found at crime scene, outside a living cell. Can amplify small quantities of dna many million times. Step 1: dna heated to separate it, highly temperature dependent. Step 2: primers added, hybridize with the strands. Step 3: dna polymerase and free nucleotides added, rebuilds each of the separated strands. Step 4: cycle repeated 25 to 30 times. With this technique sample size not a limitation. Portions of dna sequence repeat multiple times: called tandem repeats. >30% of human dna made of repeating segments.
