What is non allelic gene conversion?

What is non allelic gene conversion?

Abstract. Gene conversion is the copying of a genetic sequence from a “donor” region to an “acceptor.” In nonallelic gene conversion (NAGC), the donor and the acceptor are at distinct genetic loci.

What is somatic gene conversion?

Abstract. Gene conversion is a type of homologous recombination that leads to transfer of genetic information among homologous DNA sequences.

What is heteroduplex DNA?

A heteroduplex is a double-stranded (duplex) molecule of nucleic acid originated through the genetic recombination of single complementary strands derived from different sources, such as from different homologous chromosomes or even from different organisms.

What is unidirectional segmental gene conversion?

Gene conversion is a unidirectional exchange of sequence information between similar sequences, wherein one stretch of sequence is used as a template to ‘repair’ or ‘correct’ another stretch of sequence.

Why does heteroduplex DNA form?

heteroduplex DNA Double-stranded DNA in which the two strands are derived from different DNA molecules. Heteroduplex DNA is formed during genetic recombination (see Holliday intermediate) and can be produced in vitro in DNA hybridization.

What is Holliday model?

In 1964, Robin Holliday proposed a model that accounted for heteroduplex formation and gene conversion during recombination. It illustrates the critical steps of pairing of homologous duplexes, formation of a heteroduplex, formation of the recombination joint, branch migration and resolution.

How are Holliday junctions resolved?

Cleavage, or resolution, of the Holliday junction can occur in two ways. Cleavage of the original set of strands leads to two molecules that may show gene conversion but not chromosomal crossover, while cleavage of the other set of two strands causes the resulting recombinant molecules to show crossover.

How is heteroduplex formed?

Heteroduplexes are formed during late stages of PCR reactions when high levels of products, such as in nested PCR (N-PCR) are generated, and other reactants such as primers and functional polymerase, are depleted. They are also formed by the deliberate mixing of separately amplified reactions.

How is Holliday junction resolved?

Why do Holliday junctions occur?

Holliday junction, cross-shaped structure that forms during the process of genetic recombination, when two double-stranded DNA molecules become separated into four strands in order to exchange segments of genetic information.

Which protein is responsible for heteroduplex formation?

Enzymatic studies indicate that formation of the heteroduplex joint in Escherichia coli involves polymerization of RecA protein on single-stranded DNA (ssDNA) and pairing of the RecA–ssDNA nucleoprotein complex with a double-stranded DNA homologue (reviewed in refs. 1 and 2).

What is a non crossover gene conversion event?

Non-crossover gene conversion events are mainly produced by Synthesis Dependent Strand Annealing (SDSA). This process involves limited informational exchange, but not physical exchange of DNA, between the two participating homologous chromosomes at the site of the conversion event, and little genetic variation is produced.

What is non allelic/ectopic gene conversion?

Nonallelic/ectopic gene conversion. Recombination occurs not only during meiosis, but also as a mechanism for repair of double-strand breaks (DSBs) caused by DNA damage. These DSBs are usually repaired using the sister chromatid of the broken duplex and not the homologous chromosome, so they would not result in allelic conversion.

When does gene conversion occur during recombinational repair?

Gene conversion may also occur during recombinational repair involving a DHJ, and this gene conversion may be associated with physical recombination of the DNA duplexes on the two sides of the DHJ. Biased gene conversion (BGC) occurs when one allele has a higher probability of being the donor than the other in a gene conversion event.

What drives gene conversion events in globulin genes?

In the studies of human globulin genes, it has long been supported that the gene conversion event or branch migration events can either be promoted or inhibited by the specific motifs that exist in the vicinity of the DNA sequence (Papadakis and Patrinos]