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Chapter 11: An Introduction to Human
Genome
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A linear polynucleotide consisting of four
types of monomeric nucleotides
Each nucleotide contains:
 Deoxyribose, a Nitrogenous base, and a
Phosphate group
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Four 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
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Renaturation (reannealing)
Euchromatin
Heterochromatin
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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
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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 polymorphism
Length polymorphism
DNA markers
 Genetic mapping
 Forensic DNA profiling
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Majority are Single-nucleotide
polymorphisms (SNP)
Alleles
 Homozygous
 Heterozygous
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Genotype- combination of alleles at any
given locus
 DNA profile
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