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Definition of Chiasm: Their meanings, concepts and importance
Definition: Chiasm and its importanceCHIASM (from Gr. χίασμα, - ατος, cross layout, as the letter χ) is the crossover between chromatids not sisters in the process of meiotic recombination, as it can be viewed cytogenetically (crossover is exclusive homologous chromosomes between their chromatics not sisters).
An average of fifty-two CHIASMA evenly distributed among the 23 pairs of homologous chromosomes can be observed in a human male meiosis. In female meiosis occur more CHIASMA (98) presenting an average close to a CHIASM. Each of the sister chromatid has a 50% probability of establishing a concrete CHIASM, so the fraction of recombination (recombination frequency) maximum expected between two locus is 0.5.
Concept: Chiasm and what isChiasma is a concept that comes from the Greek language, whose etymology goes back to something that has cross. The notion is used in biology to name to the crossing that perform certain structures of organic.
Arguably, therefore, CHIASM is cross-breeding of a pair of chromosomes that are in contact in meiosis. In prophase development, these elements are recombined. It is important to highlight that in female meiosis takes the form one larger number of CHIASMA than in male meiosis.
One of the most important CHIASMA is the optic CHIASM. It is the partial crossover of optic nerves, more precisely of its axonal fibers. This CHIASMA, which occurs in the brain, means that half of the left optic nerve fibers pass to the right optical tape and vice versa.
As a result of this CHIASMA, images that are created on a retina move to the opposite cerebral sector. The optic nerves, once they cross the CHIASM, begin to be called optic tracts.
It should be noted that the optic CHIASM may suffer various disorders and diseases, including injuries that, through compression, causing optic atrophy. A disease of the pituitary gland also affect this CHIASMA.
CHIASM, on the other hand, is the name of an Argentine company of technology that offers consulting services and technical support. Also referred to as CHIASM to an audiovisual project driven by Colombian artists Clemencia Echeverri, Andrés Burbano, Bárbara Santos and Santiago Ortiz.