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In some types of prion in fungi this change is continuous and direct; the information flow is Protein → Protein. Some scientists such as Alain E. Bussard and Eugene Koonin have argued that prion-mediated inheritance violates the central dogma of molecular biology.
Others insert additional amino acids into the protein or cause an abnormally short protein to be made. These mutations cause the cell to make prion proteins with an abnormal structure. The abnormal protein PrP Sc accumulates in the brain and destroys nerve cells, which leads to the mental and behavioral features of prion diseases. [citation needed]
A prion / ˈ p r iː ɒ n / ⓘ is a misfolded protein that induces misfolding in normal variants of the same protein, leading to cellular death. Prions are responsible for prion diseases, known as transmissible spongiform encephalopathy (TSEs), which are fatal and transmissible neurodegenerative diseases affecting both humans and animals.
Structural inheritance or cortical inheritance is the transmission of an epigenetic trait in a living organism by a self-perpetuating spatial structures. This is in contrast to the transmission of digital information such as is found in DNA sequences, which accounts for the vast majority of known genetic variation.
Another example is seen in prions, special proteins that are capable of changing the structure of normal proteins to match their own. The prions use themselves as a template and then edit the folding of normal proteins to match their own folding pattern. The changes in the protein folding results in an alteration in the normal protein's function.
There are two distinctive mapping approaches used in the field of genome mapping: genetic maps (also known as linkage maps) [7] and physical maps. [3] While both maps are a collection of genetic markers and gene loci, [8] genetic maps' distances are based on the genetic linkage information, while physical maps use actual physical distances usually measured in number of base pairs.
The subsequent demonstration that human prion diseases were transmissible reinforced the importance of spongiform change as a diagnostic feature, reflected in the use of the term "spongiform encephalopathy" for this group of disorders. Prions appear to be most infectious when in direct contact with affected tissues.
If a pattern is restricted to the C-terminal of a sequence, the pattern is suffixed with '>'. The character '>' can also occur inside a terminating square bracket pattern, so that S[T>] matches both "ST" and "S>". If e is a pattern element, and m and n are two decimal integers with m <= n, then: e(m) is equivalent to the repetition of e exactly ...