Search results
Results from the WOW.Com Content Network
Non-allelic homologous recombination (NAHR) is a form of homologous recombination that occurs between two lengths of DNA that have high sequence similarity, but are not alleles. [ 1 ] [ 2 ] [ 3 ] It usually occurs between sequences of DNA that have been previously duplicated through evolution, and therefore have low copy repeats (LCRs).
Gene conversion is the process by which one DNA sequence replaces a homologous sequence such that the sequences become identical after the conversion. [1] Gene conversion can be either allelic, meaning that one allele of the same gene replaces another allele, or ectopic, meaning that one paralogous DNA sequence converts another.
These rules (patterns) are not without exceptions. Non-allelic mutants may occasionally fail to complement (this is known as "non-allelic non-complementation" or "unlinked non-complementation"). This is an uncommon occurrence that depends on the type of mutants being investigated. Two mutations, for example, could be synthetically dominant ...
An example in dog coat genetics is the homozygosity with the allele "e e" on the Extension-locus making it impossible to produce any other pigment than pheomelanin. Although the allele "e" is a recessive allele on the extension-locus itself, the presence of two copies leverages the dominance of other coat colour genes.
Coalescent theory is a model of how alleles sampled from a population may have originated from a common ancestor.In the simplest case, coalescent theory assumes no recombination, no natural selection, and no gene flow or population structure, meaning that each variant is equally likely to have been passed from one generation to the next.
For example, Huntington disease is an autosomal dominant condition, but up to 25% of individuals with the affected genotype will not develop symptoms until after age 50. [17] Another factor that can complicate Mendelian inheritance patterns is variable expressivity , in which individuals with the same genotype show different signs or symptoms ...
Fitness epistasis (an interaction between non-allelic genes) is positive (in other words, diminishing, antagonistic or buffering) when a loss of function mutation of two given genes results in exceeding the fitness predicted from individual effects of deleterious mutations, and it is negative (that is, reinforcing, synergistic or aggravating ...
Allelic exclusion is a process by which only one allele of a gene is expressed while the other allele is silenced. [1] This phenomenon is most notable for playing a role in the development of B lymphocytes , where allelic exclusion allows for each mature B lymphocyte to express only one type of immunoglobulin .