Biology Reference
In-Depth Information
DNA sequencing using the first-generation Sanger method now is highly
automated, using bases labeled with fluorescent dyes. Scanners read sequences
directly and sequence analysis is automated, thereby reducing costs and increas-
ing speed. Automated sequencing methods were used for the very large-scale
sequencing required to sequence the entire
Drosophila melanogaster
genome.
The information obtained from the
Drosophila
Genome Project has revolution-
ized both fundamental and applied aspects of insect genetics. Subsequently,
several next-generation (NextGen) sequencing methods were developed
that are more rapid, less expensive, and provide massive amounts of data.
These NextGen methods make it possible to resequence genomes, do
de novo
sequencing of whole genomes, and sequence cDNAs (transcriptomes) inexpen-
sively and rapidly.
As a by-product of genome projects, new scientific disciplines, called
“-Omics,” have been developed. Genomics is providing insight into develop-
ment, speciation, protein interactions, and evolution. Proteomics involves under-
standing the structure and function of the proteins encoded by the genes.
Transcriptomics studies which genes are transcribed during development in spe-
cific tissues. Comparative genomics allow scientists to compare whole genomes
of multiple species to understand the evolution of genomes. Because genom-
ics and proteomics produce huge amounts of data, biologists need to use com-
puters and other information-management tools, generating a new discipline
called bioinformatics. The next few years should see the completion of thou-
sands of genome projects of arthropods, projects that should provide insight
into arthropod biology and evolution never before feasible.
7.2 Introduction
DNA sequencing is an important component of many molecular genetics proj-
ects. Sequencing often is a necessary component of a project, whereas in other
cases it is the desired end point and the sequences are used in taxonomic, eco-
logical, or evolutionary studies. Advances in technology have made it feasible
to sequence entire genomes. Such sequencing is revolutionizing both basic and
applied knowledge of gene structure, gene function, and evolution. In identi-
fying the sequences of promoters, protein-coding sequences, and noncoding
regions of DNA in genomic or mitochondrial DNA, it is possible to deduce rela-
tionships between organisms and to reconstruct their evolutionary history.
The development of extensive computerized databases of DNA and pro-
tein sequences allows hypotheses to be constructed and tested regarding the
structure and function of proteins and their secondary structures. All of these
