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 groupFour bases:

Adenine (A) Cytosine (C) Guanine (G) Thymine (T)

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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

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Denaturation Melting curve Melting Temperature

Renaturation (reannealing)EuchromatinHeterochromatin

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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

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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

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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

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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

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Differences between individual genomes

Sequence polymorphismLength polymorphismDNA markers

Genetic mapping Forensic DNA profiling

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Majority are Single-nucleotide polymorphisms (SNP)

Alleles Homozygous Heterozygous

Genotype- combination of alleles at any given locus DNA profile

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