Chapter Summary

• Methods of DNA sequencing involve miniaturization and computerized analysis. Review Figure 17.1, Animations 17.1, 17.2

• Genomes are sequenced in overlapping fragments, and then the fragments are lined up to give the final sequence. Review Figure 17.2

• The analysis of genome sequences gives information about protein-coding and noncoding regions.

• DNA sequencing is used to study the genomes of prokaryotes that are important to humans and ecosystems.

• Metagenomics is the identification of DNA sequences from multiple organisms from a bulk environmental sample (such as soil or seawater). Review Figure 17.3

• Transposable elements (or transposons) and composite transposons can move about the genome. Review Figure 17.4

• Transposon mutagenesis can be used to inactivate genes one by one. The mutated organism can be tested for survival and a minimal set of essential genes described. Review Figure 17.5

• Review Focus: Key Figure 17.6

• Comparisons of genome sequences from model organisms have revealed some common features of the eukaryotic genomes as well as specialized genes for cellular compartmentalization, development, and features unique to plants. Review Tables 17.2, 17.3, 17.4, 17.5, Figures 17.7, 17.8

• Some eukaryotic genes exist as members of gene families. Proteins may be made from these closely related genes at different times and in different tissues. Some members of gene families may be nonfunctional pseudogenes. Review Figure 17.9

• Repeated sequences are present in the eukaryotic genomes. Review Table 17.6

• Moderately repetitive sequences include those coding for rRNA and transposons. Review Figure 17.10

• The haploid human genome has 3.2 billion bp.

• Only about 1.2 percent of the genome codes for proteins; the rest consists of repeated sequences and noncoding DNA.

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• Most human genes have introns, and alternative splicing leads to the production of more than one protein per gene.

• SNP genotyping (haplotype mapping) correlates variations in the genome with diseases or drug sensitivity. It may lead to precision medicine. Review Figure 17.12

• Pharmacogenomics uses DNA and amino acid sequence data to inform drug development and testing. Review Figure 17.13

• The proteome is the complete set of proteins in a cell, tissue, or organism at a given time.

• There are more proteins than there are protein-coding genes in the genome.

• The proteome can be analyzed using chemical methods that separate and identify proteins.

• The metabolome is the complete set of small molecules present in a cell, tissue, or organism under defined conditions.