Genomics is the study of an organism's
genome and the use of the genes. It deals with the systematic use of genome
information, associated with other data, to provide answers in biology,
medicine, and industry.
Genomics appeared in the 1980s and took off in the 1990s with
the initiation of genome projects for several species.
The related field of genetics is the study of genes and their
role in inheritance.
Genomics has the potential of offering new therapeutic methods
for the treatment of some diseases, as well as new diagnostic methods. Other
applications are in the food and agriculture sectors.
The major tools and methods related to genomics are
bioinformatics, genetic analysis, measurement of gene expression, and
determination of gene function.
Comparison of genomes has resulted in some surprising biological
discoveries. If a particular DNA sequence or pattern is present among many
members of a clade, that sequence is said to have been conserved among the
species, implying that it confers a selective advantage to the organisms.
Experimental investigation of these sequences (revealed by genomic sequencing)
has shown that some are transcribed into small RNA molecules, although the
functions of these RNAs were not immediately apparent.
The identification of similar sequences (including many genes)
in two distantly related organisms, but not in other members of one of the
clades, has led to the theory that these sequences were acquired by horizontal
gene transfer. This phenomenon is most prominent in thermophilic bacteria, where
it seems that genes were transferred from Archaea to Eubacteria. It has also
been noticed that bacterial genes exist in eukaryotic nuclear genomes and that
these genes generally encode mitochondrial and plastid proteins, giving support
to the endosymbiotic theory of the origin of these organelles.
The first genome to be sequenced in its entirety was that of
bacteriophage FX174 (5,368 kb) in 1980.
The first free-living organism to be sequenced was that of
Haemophilus influenzae (1.8Mb) in 1995, and since then genomes are being
sequenced at a rapid pace. A rough draft of the human genome was completed by
the Human Genome Project in early 2001 amid much fanfare.