Answer:
<h2> DNA double-strand breaks are repaired by two main pathways( routes): </h2><h2>i) Non-homologous end joining and </h2><h2>ii) homologous recombination
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Explanation:
All organisms suffer by double-strand breaks (DSBs) in their DNA.
DSBs caused by exposure to exogenous agents such as radiations, also by certain chemicals, and through endogenous processes, including DNA replication and repair.
Double-strand break repair:
The processing and repair of DSBs can lead to mutations, they can also lead to loss of heterozygosity, and chromosome rearrangements that can result into cell death or cancer.
DNA double-strand breaks are repaired by two main pathways( routes):
i) Non-homologous end joining and
ii) homologous recombination
.
Homologous recombination- it takes place by means of replication, using the homologous strand as template. Homologous recombination therefore requires extensive regions of DNA homology in another DNA duplex, and there is no loss of genetic information normally.
Non-homologous end joining- It requires no homology with a second DNA duplex and no, or only a few base pairs of, homology between the two broken DNA ends.
Homologous recombination is the mainly preferred mechanism in yeast.
Non-homologous DNA end joining is more commonly mutagenic than homologous recombination repair.
