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chiasma Syllabification: chi·as·ma
Pronunciation: /kīˈazmə/

Definition of chiasma in English:

noun (plural chiasmata-mətə)

A point at which paired chromosomes remain in contact during the first metaphase of meiosis, and at which crossing over and exchange of genetic material occur between the strands. See also optic chiasma.
Example sentences
  • A given factor s can affect the recombination rate r through a change in the number of chiasmata occurring during meiosis.
  • However, the observed differences may be conditional on the chromosomal location of the chiasmata.
  • First, it generates crossovers between homologous chromosomes that mature into visible chiasmata.


Mid 19th century: modern Latin, from Greek chiasma 'crosspiece, cross-shaped mark', from khiazein 'mark with the letter chi'.

Definition of chiasma in:
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