Forensic Biology by Richard LiStructure & PropertiesSlide 3Slide 4Slide 5Human ChromosomesHuman Nuclear GenomeSlide 8Human DNA PolymorphismsSlide 10Chapter 11: An Introduction to Human GenomeA linear polynucleotide consisting of four types of monomeric nucleotidesEach nucleotide contains:Deoxyribose, a Nitrogenous base, and a Phosphate groupFour bases:Adenine (A)Cytosine (C)Guanine (G)Thymine (T)Forensic Biology by Richard Li 2The Double HelixWatson & CrickB-Form of DNA- right handed turns and two grooves that spiral (major & minor)Stabilized by chemical interactionsA always pairs with TC always pairs with GForensic Biology by Richard Li 3DenaturationMelting curveMelting TemperatureRenaturation (reannealing)EuchromatinHeterochromatinForensic Biology by Richard Li 4Human ChromosomesShort arm (p) & Long arm (q)Centromeres- DNA sequences found near the point of attachment of mitotic or meiotic spindle fibersTelomeres- ends of chromosomesForensic Biology by Richard Li 5Gametes- spermatozoa and ova▪Haploid▪22 autosomes + 1 sex chromosomeSomatic Cells- most other cells except reproductive▪Diploid▪Two copies of each autosome + 2 sex chromosomes= 46Forensic Biology by Richard Li 6Human genome- one set of 23 chromosomesContains biological information to perform biological functionsNuclear and Mitochondrial Genomes3.2 billion base pairs30,000 – 40,000 genes▪Encode information for the synthesis of proteinsHuman Genome Project (1990)- ▪2.6 billion base pairs (80%) completedForensic Biology by Richard Li 7Intergenic Non-coding Sequences60% of human genome sequenceRepetitive DNA▪Genome-wide (interspersed repeats)▪SINEs, LINEs, LTR▪Tandemly repeated DNA▪Repeat units that are placed next to each other in an array▪Satellite DNA▪Minisatellites▪MicrosatellitesForensic Biology by Richard Li 8Differences between individual genomes Sequence polymorphismLength polymorphismDNA markersGenetic mappingForensic DNA profilingForensic Biology by Richard Li 9Majority are Single-nucleotide polymorphisms (SNP)AllelesHomozygousHeterozygousGenotype- combination of alleles at any given locusDNA profileForensic Biology by Richard Li