Genomes and Their Evolution

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European Molecular Biology Laboratory

DNA Data Bank of Japan

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Genbank, the NCBI database of sequences, doubles its data approximately every 18 months

Software is available that allows online visitors to search Genbank for matches to:

A specific DNA sequence

A predicted protein sequence

Common stretches of amino acids in a protein

The NCBI website also provides 3-D views of all protein structures that have been determined

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Fig. 21-4

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Identifying Protein-Coding Genes Within DNA Sequences

Computer analysis of genome sequences helps identify sequences likely to encode proteins

Comparison of sequences of “new” genes with those of known genes in other species may help identify new genes

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Understanding Genes and Their Products at the Systems Level

Proteomics is the systematic study of all proteins encoded by a genome

Proteins, not genes, carry out most of the activities of the cell

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How Systems Are Studied: An Example

A systems biology approach can be applied to define gene circuits and protein interaction networks

Researchers working on Drosophila used powerful computers and software to predict 4,700 protein products that participated in 4,000 interactions

The systems biology approach is possible because of advances in bioinformatics

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Fig. 21-5

Proteins

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Application of Systems Biology to Medicine

A systems biology approach has several medical applications:

The Cancer Genome Atlas project is currently monitoring 2,000 genes in cancer cells for changes due to mutations and rearrangements

Treatment of cancers and other diseases can be individually tailored following analysis of gene expression patterns in a patient

In future, DNA sequencing may highlight diseases to which an individual is predisposed

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Fig. 21-6

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Concept 21.3 Genomes vary in size, number of genes, and gene density

By summer 2007, genomes had been sequenced for 500 bacteria, 45 archaea, and 65 eukaryotes including vertebrates, invertebrates, and plants

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