Chapter 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 Li2

 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 G Forensic Biology by Richard Li3

 Denaturation  Melting curve  Melting Temperature  Renaturation (reannealing)  Euchromatin  Heterochromatin Forensic Biology by Richard Li4

 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 chromosomes Forensic Biology by Richard Li5

 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= 46 Forensic Biology by Richard Li6

 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%) completed Forensic Biology by Richard Li7

 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 ▪ Microsatellites Forensic Biology by Richard Li8

 Differences between individual genomes  Sequence polymorphism  Length polymorphism  DNA markers  Genetic mapping  Forensic DNA profiling Forensic Biology by Richard Li9

 Majority are Single-nucleotide polymorphisms (SNP)  Alleles  Homozygous  Heterozygous  Genotype- combination of alleles at any given locus  DNA profile Forensic Biology by Richard Li10