How can homologous recombination be used to delete a gene?
Scientists currently delete genes by manipulating a process known as homologous recombination. Nucleotide sequences change places with the target gene during homologous recombination and are left behind as a genetic scar, undermining the effectiveness of subsequent deletions.
What is homologous recombination in gene therapy?
In meiotic eukaryotic cells, homologous recombination is the way cells exchange genetic material between homologous chromosomes to create genetic diversity and is the way that cells synapse homologous chromosomes to allow proper chromosomal segregation.
What are the steps in homologous recombination?
Homologous recombination can be divided into three key steps: strand exchange, branch migration and resolution. The identification of a protein complex that catalyses branch migration and Holliday junction resolution argues that the mechanism of homologous recombination is conserved from bacteria to man.
How does homologous recombination repair?
In cells that divide through mitosis, homologous recombination repairs double-strand breaks in DNA caused by ionizing radiation or DNA-damaging chemicals. It does so by facilitating chromosomal crossover, in which regions of similar but not identical DNA are exchanged between homologous chromosomes.
Can a person’s DNA be erased?
Gene therapy , or somatic gene editing, changes the DNA in cells of an adult or child to treat disease, or even to try to enhance that person in some way. The changes made in these somatic (or body) cells would be permanent but would only affect the person treated.
What does homologous recombination do?
In eukaryotes, homologous recombination occurs during meiosis, playing a critical role in the repair of double-stranded nicks in DNA and increasing genetic diversity by enabling the shuffling of genetic material during chromosomal crossover.
What phase does homologous recombination occur?
Homologous recombination repairs DNA before the cell enters mitosis (M phase). It occurs during and shortly after DNA replication, in the S and G2 phases of the cell cycle, when sister chromatids are more easily available.
What is gene deletion?
​Deletion. = Deletion is a type of mutation involving the loss of genetic material. It can be small, involving a single missing DNA base pair, or large, involving a piece of a chromosome.
How does deletion happen?
Deletions can be caused by errors in chromosomal crossover during meiosis, which causes several serious genetic diseases. Deletions that do not occur in multiples of three bases can cause a frameshift by changing the 3-nucleotide protein reading frame of the genetic sequence.
Can a homologous recombination cause a deletion?
Deletions, though, can occur by illegitimate recombination (NHEJ) or by HR. In fact, many of the deletion events that have been mapped appear to have been mediated by regions of homology; some of these are outlined below.
Is the loss of a chromosome due to recombination?
Though chromosome loss is not likely to be due to a recombination event, both gene conversion and deletion are. Gene conversion is undisputedly an HR event, where genetic information is copied from one locus to another. Deletions, though, can occur by illegitimate recombination (NHEJ) or by HR.
Which is a mechanism for the loss of heterozygosity?
The major mechanisms by which such a loss of heterozygosity occurs are chromosomal loss, gene conversion and deletion ( 29 ). Though chromosome loss is not likely to be due to a recombination event, both gene conversion and deletion are. Gene conversion is undisputedly an HR event, where genetic information is copied from one locus to another.
What happens when HR occurs between dispersed homologous sequences?
Such HR events between dispersed homologous sequences may result in not only deletions, but also gene duplications or translocations. These types of genomic rearrangement have been observed to be the cause of several different genetic diseases, including cancer.