Definition of chiasma in English:

chiasma

nounPlural chiasmata kʌɪˈazməkɪˈazməkaɪˈæzmə

1Anatomy
The X-shaped structure formed at the point below the brain where the two optic nerves cross over each other.
Example sentencesExamples
- The dura that invests the optic chiasma can be traced from the chiasma along the optic nerve.
2Biology
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.
〔生〕（染色体）交叉。参见 OPTIC CHIASMA
Example sentencesExamples
- Genetic recombination is absent and no chiasmata are formed in bivalents.
- A given factor s can affect the recombination rate r through a change in the number of chiasmata occurring during meiosis.
- During meiosis, homologous chromosomes become physically connected by the formation of chiasmata.
- First, it generates crossovers between homologous chromosomes that mature into visible chiasmata.
- However, the observed differences may be conditional on the chromosomal location of the chiasmata.

Origin

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

Definition of chiasma in US English:

chiasma

nounkīˈazməkaɪˈæzmə

1Anatomy
The X-shaped structure formed at the point below the brain where the two optic nerves cross over each other.
Example sentencesExamples
- The dura that invests the optic chiasma can be traced from the chiasma along the optic nerve.
2Biology
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.
〔生〕（染色体）交叉。参见 OPTIC CHIASMA
Example sentencesExamples
- A given factor s can affect the recombination rate r through a change in the number of chiasmata occurring during meiosis.
- Genetic recombination is absent and no chiasmata are formed in bivalents.
- During meiosis, homologous chromosomes become physically connected by the formation of chiasmata.
- 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.

Origin

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

词汇	chiasma
释义	Definition of chiasma in English: chiasma nounPlural chiasmata kʌɪˈazməkɪˈazməkaɪˈæzmə 1Anatomy The X-shaped structure formed at the point below the brain where the two optic nerves cross over each other. Example sentencesExamples The dura that invests the optic chiasma can be traced from the chiasma along the optic nerve. 2Biology 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. 〔生〕（染色体）交叉。参见 OPTIC CHIASMA Example sentencesExamples Genetic recombination is absent and no chiasmata are formed in bivalents. A given factor s can affect the recombination rate r through a change in the number of chiasmata occurring during meiosis. During meiosis, homologous chromosomes become physically connected by the formation of chiasmata. First, it generates crossovers between homologous chromosomes that mature into visible chiasmata. However, the observed differences may be conditional on the chromosomal location of the chiasmata. Origin Mid 19th century: modern Latin, from Greek chiasma 'crosspiece, cross-shaped mark', from khiazein 'mark with the letter chi'. Definition of chiasma in US English: chiasma nounkīˈazməkaɪˈæzmə 1Anatomy The X-shaped structure formed at the point below the brain where the two optic nerves cross over each other. Example sentencesExamples The dura that invests the optic chiasma can be traced from the chiasma along the optic nerve. 2Biology 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. 〔生〕（染色体）交叉。参见 OPTIC CHIASMA Example sentencesExamples A given factor s can affect the recombination rate r through a change in the number of chiasmata occurring during meiosis. Genetic recombination is absent and no chiasmata are formed in bivalents. During meiosis, homologous chromosomes become physically connected by the formation of chiasmata. 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. Origin Mid 19th century: modern Latin, from Greek chiasma ‘crosspiece, cross-shaped mark’, from khiazein ‘mark with the letter chi’.
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