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&nbsp;Chiasma or crossover refers to the visible point where paired maternal and paternal [[Homologous_chromosome|homologous]] [[Homologous_chromosomes|chromosomes]] join during [[Meiosis|meiosis ]]1 and then crossover. This[[Recombination|recombination]] occurs when a segment of one paternal [[Chromatid|chromatid]] is replaced by the [[complementary|complementary]] form of the other maternal [[chromatid|chromatid]].&nbsp;<ref>Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts and Peter Walter, 2008. Molecular biology of the cell. 5th edition. New York: Garland science.</ref>
&nbsp;Chiasma or crossover refers to the visible point where paired maternal and paternal [[Homologous chromosome|homologous]] [[Homologous chromosomes|chromosomes]] join during [[Meiosis|meiosis ]]1 and then crossover. This&nbsp;[[Recombination|recombination]] occurs when a segment of one paternal [[Chromatid|chromatid]] is replaced by the [[Complementary|complementary]] form of the other maternal [[Chromatid|chromatid]].&nbsp;<ref>Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts and Peter Walter, 2008. Molecular biology of the cell. 5th edition. New York: Garland science.</ref>  


There are 2 [[nuclear division|nuclear divisions]] in [[Meiosis|meiosis]], and a chiasma forms in the first division of [[Meiosis|meiosis]] 1. The duplicated [[Homologues|homologs]] align with each other and swap genetic information&nbsp;[[Recombination|(recombination)]].
There are 2 [[Nuclear division|nuclear divisions]] in [[Meiosis|meiosis]], and a chiasma forms in the first division of [[Meiosis|meiosis]] 1. The duplicated [[Homologues|homologs]] align with each other and swap genetic information&nbsp;[[Recombination|(recombination)]].  


Crossover happens between 2 non-sister [[Chromatids|chromatids]]. The chiasma can be seen at the point where the [[Homologues|homologs]]&nbsp;join in [[Prophase|prophase]] 1, when the [[Synaptonemal_Complex|synaptonemal complex]] disassembles and ''begin&nbsp;to separate.&nbsp;<ref>Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts and Peter Walter, 2008. Molecular biology of the cell. 5th edition. New York: Garland science.</ref>
Crossover happens between 2 non-sister [[Chromatids|chromatids]]. The chiasma can be seen at the point where the [[Homologues|homologs]]&nbsp;join in [[Prophase|prophase]] 1, when the [[Synaptonemal Complex|synaptonemal complex]] disassembles and ''begin&nbsp;to separate.&nbsp;<ref>Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts and Peter Walter, 2008. Molecular biology of the cell. 5th edition. New York: Garland science.</ref>''


 
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Revision as of 16:20, 27 November 2013

 Chiasma or crossover refers to the visible point where paired maternal and paternal homologous chromosomes join during meiosis 1 and then crossover. This recombination occurs when a segment of one paternal chromatid is replaced by the complementary form of the other maternal chromatid[1]

There are 2 nuclear divisions in meiosis, and a chiasma forms in the first division of meiosis 1. The duplicated homologs align with each other and swap genetic information (recombination).

Crossover happens between 2 non-sister chromatids. The chiasma can be seen at the point where the homologs join in prophase 1, when the synaptonemal complex disassembles and begin to separate. [2]


References: =

  1. Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts and Peter Walter, 2008. Molecular biology of the cell. 5th edition. New York: Garland science.
  2. Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts and Peter Walter, 2008. Molecular biology of the cell. 5th edition. New York: Garland science.