Genomes and Their Evolution

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Slide 1

Reading the Leaves from the Tree of Life

Complete genome sequences exist for a human, chimpanzee, E. coli, brewer’s yeast, nematode, fruit fly, house mouse, rhesus macaque, and other organisms

Comparisons of genomes among organisms provide information about the evolutionary history of genes and taxonomic groups

Slide 2

Genomics is the study of whole sets of genes and their interactions

Bioinformatics is the application of computational methods to the storage and analysis of biological data

Slide 3

Fig. 21-1

Slide 4

Concept 21.1: New approaches have accelerated the pace of genome sequencing

The most ambitious mapping project to date has been the sequencing of the human genome

Officially begun as the Human Genome Project in 1990, the sequencing was largely completed by 2003

The project had three stages:

Genetic (or linkage) mapping

Physical mapping

DNA sequencing

Slide 5

Three-Stage Approach to Genome Sequencing

A linkage map (genetic map) maps the location of several thousand genetic markers on each chromosome

A genetic marker is a gene or other identifiable DNA sequence

Recombination frequencies are used to determine the order and relative distances between genetic markers

Slide 6

Fig. 21-2-1

Cytogenetic map

Genes located

by FISH

Chromosome

bands

Slide 7

Fig. 21-2-2

Cytogenetic map

Genes located

by FISH

Chromosome

bands

Linkage mapping

1

Genetic

markers

Slide 8

Fig. 21-2-3

Cytogenetic map

Genes located

by FISH

Chromosome

bands

Linkage mapping

1

2

Genetic

markers

Physical mapping

Overlapping

fragments

Slide 9

Fig. 21-2-4

Cytogenetic map

Genes located

by FISH

Chromosome

bands

Linkage mapping

1

2

3

Genetic

markers

Physical mapping

Overlapping

fragments

DNA sequencing

Slide 10

A physical map expresses the distance between genetic markers, usually as the number of base pairs along the DNA