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.
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2 See also 3 Sources and external links |
It is often stated that such-and-such an organism shares X percent of its DNA with humans. Here is a list of genetic similarity to humans, with sources, where known.
Perhaps a geneticist (or should that be genomicist?) would care to comment on the significance, if any, of these statistics.
Dog 95% (Jon Entine in the San Francisco Examiner)
Roundworm 74% (Jon Entine in the San Francisco Examiner)
Banana 50% (source: Americans for Medical Progress)
Genetic similarity
Human 99.9% (quoted by President Clinton, Jan 2000, State of the Union address;
also Human Genome Project)
100% (identical twins)
Chimpanzee 98.4% (sources: Americans for Medical Progress;
Jon Entine in the San Francisco Examiner)
98.7% (Richard Mural of Celera, quoted on MSNBC)
Bonobo equal to chimpanzee
Gorilla 98.38% (based on study of intergenic nonrepetitive DNA in Am J Hum Genet. 2001 Feb;68(2):444-56)
Mouse 98% (source: Americans for Medical Progress)
See also
Sources and external links
