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Indeed, if the somatic L1 insertions occurs in a progenitor cell, the unique variant could be used to trace the progenitor cell's development, localization, and spreading through the brain. On the contrary, if the somatic L1 insertion occurs late in development, it will be present just in a single cell or in a small group of cells. Therefore ...
Somatic mutations that occur later in an organism's life can be hard to detect, as they may affect only a single cell—for instance, a post-mitotic neuron; [3] [4] improvements in single cell sequencing are therefore an important tool for the study of somatic mutation. [5]
Single nucleotide substitutions with an allele frequency of less than 1% are sometimes called single-nucleotide variants (SNVs). [8] "Variant" may also be used as a general term for any single nucleotide change in a DNA sequence, [9] encompassing both common SNPs and rare mutations, whether germline or somatic.
The frequency of mutations in mouse somatic tissue (brain, liver, Sertoli cells) was compared to the mutation frequency in male germline cells at sequential stages of spermatogenesis. [3] The spontaneous mutation frequency was found to be significantly higher (5 to 10-fold) in the somatic cell types than in the male germline cells. [3]
Somatic hypermutation (or SHM) is a cellular mechanism by which the immune system adapts to the new foreign elements that confront it (e.g. microbes).A major component of the process of affinity maturation, SHM diversifies B cell receptors used to recognize foreign elements and allows the immune system to adapt its response to new threats during the lifetime of an organism. [1]
A postzygotic mutation (or post-zygotic mutation) is a change in an organism's genome that is acquired during its lifespan, instead of being inherited from its parent(s) through fusion of two haploid gametes. Mutations that occur after the zygote has formed can be caused by a variety of sources that fall under two classes: spontaneous mutations ...
Somatic recombination, as opposed to the genetic recombination that occurs in meiosis, is an alteration of the DNA of a somatic cell that is inherited by its daughter cells. The term is usually reserved for large-scale alterations of DNA such as chromosomal translocations and deletions and not applied to point mutations .
An example of this is the modern cultivated species of wheat, Triticum aestivum L., a hexaploid species whose somatic cells contain six copies of every chromatid. [citation needed] The frequency of spontaneous mutations is significantly lower in advanced male germ cells than in somatic cell types from the same individual. [7]