What is meant by homologous recombination?

What is meant by homologous recombination?

Homologous recombination is a type of genetic recombination that occurs during meiosis (the formation of egg and sperm cells). Paired chromosomes from the male and female parent align so that similar DNA sequences from the paired chromosomes cross over each other.

What are the steps of homologous recombination?

Homologous recombination can be conceptually divided into three stages: presynapsis, synapsis, and postsynapsis. During presynapsis, DSB ends are recognized and processed to a 3′-OH ending single-stranded tail (steps 1-2). In synapsis, DNA strand invasion by the Rad51-ssDNA filament generates a D-loop (step 3).

What is the role of homologous recombination?

Key Points. Homologous recombination (HR) has an important role in DNA repair, DNA replication, meiotic chromosome segregation and telomere maintenance. HR is tightly regulated by DNA helicases. A defect in, or deregulation of, HR can lead to cell-cycle arrest, genome destabilization and cancer formation.

What is homologous recombination and what is its outcome?

Homologous recombination (HR) is the genetic consequence of physical exchange between two aligned identical DNA regions on two separate chromosomes or on the same chromosome. HR mostly occurs between homologous chromosomes bearing distinct markers surrounding the exchange region.

What is an example of recombination?

Recombination occurs when two molecules of DNA exchange pieces of their genetic material with each other. One of the most notable examples of recombination takes place during meiosis (specifically, during prophase I), when homologous chromosomes line up in pairs and swap segments of DNA.

What proteins are used in homologous recombination?

The central protein involved in homologous recombination is RecA, which promotes the exchange of strands between homologous DNAs that causes heteroduplexes to form (Figure 5.35).

Why is homologous recombination accurate?

Homologous recombination (HR) is a molecular pathway involved in a multitude of processes, from the generation of genetic diversity to DNA repair and replication. HR provides a mechanism for the accurate repair of DNA double-strand breaks, protecting cells from chromosomal aberrations such as those seen in cancer.

What is the difference between homologous and nonhomologous recombination?

Homologous and non-homologous chromosomes are the two types chromosomes identified based on the pairing pattern of chromosomes during the metaphase 1 of meiosis. Homologous chromosomes refer to the chromosomes in the same pair while non-homologous chromosomes refer to the chromosomes in different pairs.