What are homologous DNA strands?
Homologous recombination is a type of genetic recombination in which genetic information is exchanged between two similar or identical molecules of double-stranded or single-stranded nucleic acids (usually DNA as in cellular organisms but may be also RNA in viruses).
What is homologous DNA repair?
Homologous recombination repair is a DNA repair process that includes the invasion of an undamaged DNA molecule by a damaged molecule of identical or very similar sequence. Resynthesis of the damaged region is accomplished using the undamaged molecule as a template.
How does homologous recombination repair double strand breaks in DNA?
Repair of a DNA double-strand break by homologous recombination takes place by means of replication, using the homologous strand as template (see Figure 1). Homologous recombination therefore requires extensive regions of DNA homology in another DNA duplex, and no loss of genetic information normally results.
How do you knock out a gene?
Knocking out a gene means to mutate the DNA in a way that stops the gene’s expression permanently. This is possible in all kinds of cells and organisms, using specific genetic approaches. Currently, the fastest and most direct approach to achieving specific gene knockout is to use CRISPR genome editing.
How long does homologous recombination take?
Homologous recombination (HR) HR also takes place during the meiotic cell cycle where it occurs in prophase 1 until metaphase 1 to generate crossing overs. Because HR is very cell cycle specific, the cyclin-dependent Kinases that mediate cell cycle progression are important regulators of HR.
Is homologous recombination a DNA repair?
Homologous recombination (HR) is a DNA metabolic process found in all forms of life that provides high-fidelity, template-dependent repair or tolerance of complex DNA damages including DNA gaps, DNA double-stranded breaks (DSBs), and DNA interstrand crosslinks (ICLs).
Do homologous chromosomes have identical DNA sequences?
The DNA sequences of homologous chromosomes are usually not exactly identical. These 46 chromosomes consist of 23 pairs of homologous chromosomes, or homologs, meaning each of these pairs are alike, but not necessarily identical.
Where does homologous recombination occur?
meiosis
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.
How do you overexpress a gene?
There are four main methods for introducing foreign DNA into cells: electric shock, calcium phosphate method, liposome-mediated and virus-mediated. For many ordinary cell lines, the methods of transient transfection were mostly liposome-mediated.
What is knockout allele?
A gene knockout (abbreviation: KO) is a genetic technique in which one of an organism’s genes is made inoperative (“knocked out” of the organism). Knockout organisms or simply knockouts are used to study gene function, usually by investigating the effect of gene loss.