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Illustration of a transversion: each of the 8 nucleotide changes between a purine and a pyrimidine (in red). The 4 other changes are transitions (in blue).. Transversion, in molecular biology, refers to a point mutation in DNA in which a single (two ring) purine (A or G) is changed for a (one ring) pyrimidine (T or C), or vice versa. [1]
A point mutation is a genetic mutation where a single nucleotide base is changed, inserted or deleted from a DNA or RNA sequence of an organism's genome. [1] Point mutations have a variety of effects on the downstream protein product—consequences that are moderately predictable based upon the specifics of the mutation.
Illustration of a transition: each of the 4 nucleotide changes between purines or between pyrimidines (in blue). The 8 other changes are transversions (in red).. Transition, in genetics and molecular biology, refers to a point mutation that changes a purine nucleotide to another purine (A ↔ G), or a pyrimidine nucleotide to another pyrimidine (C ↔ T).
For example, mutational biases and purifying selection favoring conservative changes are probably both responsible for the relatively high rate of transitions compared to transversions in evolving sequences. However, the Kimura (K80) model described below only attempts to capture the effect of both forces in a parameter that reflects the ...
Gene conversion resulting in mutation of the CYP21A2 gene is a common underlying genetic cause of congenital adrenal hyperplasia. Somatic gene conversion is one of the mechanisms that can result in familial retinoblastoma , a congenital cancer of the retina , and it is theorized that gene conversion may play a role in the development of ...
The combination of SSM events with point mutation is thought to account for the evolution of more complex repeat units. Mutations followed by expansion would result in the formation of new types of adjacent short tandem repeat units. For example, a transversion could change the simple two- base repeat [GA] 10 to [GA] 4 GATA[GA] 2.
Mutation bias refers to a predictable or systematic difference in rates for different types of mutation.The types are most often defined by the molecular nature of the mutational change, but sometimes they are based on downstream effects, e.g., Ostrow, et al. [1] refer to "mutational bias for body size".
The missense mutations may be classed as point accepted mutations if the mutated protein is not rejected by natural selection. A point accepted mutation — also known as a PAM — is the replacement of a single amino acid in the primary structure of a protein with another single amino acid, which is accepted by the processes of natural selection.