Search results
Results From The WOW.Com Content Network
Susumu Ohno was one of the most famous developers of this theory in his classic book Evolution by gene duplication (1970). [26] Ohno argued that gene duplication is the most important evolutionary force since the emergence of the universal common ancestor. [27] Major genome duplication events can be quite common.
[3] Rifampicin was discovered in 1965, marketed in Italy in 1968, and approved in the United States in 1971. [5] [6] [7] It is on the World Health Organization's List of Essential Medicines. [8] The World Health Organization classifies rifampicin as critically important for human medicine. [9] It is available as a generic medication. [3]
Rifampin rapidly kills fast-dividing bacilli strains as well as "persisters" cells, which remain biologically inactive for long periods of time that allow them to evade antibiotic activity. [7] In addition, rifabutin and rifapentine have both been used against tuberculosis acquired in HIV-positive patients.
If a gene duplication is preserved, the most likely fate is that random mutations in one duplicate gene copy will eventually cause the gene to become non-functional . [3] Such non-functional remnants of genes, with detectable sequence homology, can sometimes still be found in genomes and are called pseudogenes.
Gene duplication, a process which can result in free mutation; Chromosomal duplication, which can cause Bloom and Rett syndrome; Polyploidy, a phenomenon also known as ancient genome duplication; Enteric duplication cysts, certain portions of the gastrointestinal tract; Diprosopus, a form of cojoined twins also known as craniofacial duplication
[6] [7] [8] Gene redundancy has long been appreciated as a source of novel gene origination; [8] that is, new genes may arise when selective pressure exists on the duplicate, while the original gene is maintained to perform the original function, as proposed by newer models [4]. Figure 1. Common mechanisms of gene duplication.
The 2R hypothesis saw a resurgence of interest in the 1990s for two reasons. First, gene mapping data in humans and mice revealed extensive paralogy regions - sets of genes on one chromosome related to sets of genes on another chromosome in the same species, indicative of duplication events in evolution. [9]
Neofunctionalization is the process by which a gene acquires a new function after a gene duplication event. The figure shows that once a gene duplication event has occurred one gene copy retains the original ancestral function (represented by the green paralog), while the other acquires mutations that allow it to diverge and develop a new function (represented by the blue paralog).