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Chromosome segregation is the process in eukaryotes by which two sister chromatids formed as a consequence of DNA replication, or paired homologous chromosomes, separate from each other and migrate to opposite poles of the nucleus. This segregation process occurs during both mitosis and meiosis. Chromosome segregation also occurs in prokaryotes ...
Genetic recombination and recombinational DNA repair also occurs in bacteria and archaea, which use asexual reproduction. Recombination can be artificially induced in laboratory (in vitro) settings, producing recombinant DNA for purposes including vaccine development. V(D)J recombination in organisms with an adaptive immune system is a type of ...
DNA damages, if not repaired, can kill a cell by blocking DNA replication, or transcription of essential genes. When only one strand of the DNA is damaged, the lost information (nucleotide sequence) can ordinarily be recovered by repair processes that remove the damaged sequence and fill the resulting gap by copying from the opposite intact ...
Genetic recombination can be viewed as fundamentally a DNA repair process, and that when it occurs during meiosis it is an adaptation for repairing the genomic DNA that is passed on to progeny. [ 44 ] [ 45 ] Experimental findings indicate that a substantial benefit of meiosis is recombinational repair of DNA damage in the germline , as ...
Meiotic recombination allows a more independent segregation between the two alleles that occupy the positions of single genes, as recombination shuffles the allele content between homologous chromosomes. [citation needed] Recombination results in a new arrangement of maternal and paternal alleles on the same chromosome.
Recombination is important as a source of genetic diversity, as a mechanism for repairing damaged DNA, and a necessary step in the appropriate segregation of chromosomes in meiosis. [14] The presence of repeated sequence DNA makes it easier for areas of homology to align, thereby controlling when and where recombination occurs.
Gene duplication (or chromosomal duplication or gene amplification) is a major mechanism through which new genetic material is generated during molecular evolution. It can be defined as any duplication of a region of DNA that contains a gene .
At a given chiasma, an exchange of genetic material can occur between both chromatids, what is called a chromosomal crossover, but this is much more frequent during meiosis than mitosis. [1] In meiosis, absence of a chiasma generally results in improper chromosomal segregation and aneuploidy. [2]