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Non-homologous end joining can also join two different chromosomes together that had broken ends. The reason non-reciprocal translocations are dangerous is the possibility of producing a dicentric chromosome – a chromosome with two centromeres. When dicentric chromosomes form, a series of events can occur called a breakage-fusion-bridge cycle ...
Usually, all cells in an individual in a given species (plant or animal) show a constant number of chromosomes, which constitute what is known as the karyotype defining this species (see also List of number of chromosomes of various organisms), although some species present a very high karyotypic variability. In humans, mutations that would ...
Animal testing, also known as animal experimentation, animal research, and in vivo testing, is the use of non-human animals, such as model organisms, in experiments that seek to control the variables that affect the behavior or biological system under study. This approach can be contrasted with field studies in which animals are observed in ...
All known mechanisms that prevent DNA rereplication in eukaryotic organisms inhibit origin licensing. [1] Origin licensing is the preliminary step for normal replication initiation during late G1 and early S phase and involves the recruitment of the pre-replicative complex (pre-RC) to the replication origins.
In meiosis, non-sister homologous chromosomes pair with each other so that recombination characteristically occurs between non-sister homologues. In both meiotic and mitotic cells, recombination between homologous chromosomes is a common mechanism used in DNA repair .
Duplications arise from an event termed unequal crossing-over that occurs during meiosis between misaligned homologous chromosomes. The chance of it happening is a function of the degree of sharing of repetitive elements between two chromosomes. The products of this recombination are a duplication at the site of the exchange and a reciprocal ...
Genetic testing of plants and animals can be used for similar reasons as in humans (e.g. to assess relatedness/ancestry or predict/diagnose genetic disorders), [4] to gain information used for selective breeding, [5] or for efforts to boost genetic diversity in endangered populations. [6] The variety of genetic tests has expanded throughout the ...
Over time this would result in progressive shortening of both daughter chromosomes. This is known as the end replication problem. [1] The end replication problem is handled in eukaryotic cells by telomere regions and telomerase. Telomeres extend the 3' end of the parental chromosome beyond the 5' end of the daughter strand.