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Crossing over



A process occurring during meiosis wherein two chromosomes pair up and exchange segments of their genetic material.


This occurs at the stage when chromatids of homologous chromosomes pair up during synapsis, forming X-structure (chiasma). The chromatids break into segments (of matching regions), which are then exchanged with one another.

Crossing over is important because it results in new combinations of genes that are different from either parent, contributing to genetic diversity.

See also: meiosis, homologous chromosomes.

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... chromosomes designated C1 and C2, M1 and M2, and S1 and S2. No crossing over occurs. a. What combination(s) of chromosomes are possible in daughter cells following ...

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by lachatausa
Fri Mar 21, 2014 2:55 am
Forum: Genetics
Topic: genetic
Replies: 1
Views: 2196

Meiosis prophase I crossover

“Chromosomal crossover (or crossing over) is the exchange of genetic material between homologous chromosomes that results in recombinant ...

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by gs99
Fri Mar 07, 2014 9:23 pm
Forum: Molecular Biology
Topic: Meiosis prophase I crossover
Replies: 0
Views: 2622

Need an help about Drosophila genetics

Hello! I need help. My professor asks me this and I could not understand it. Can you please help me to figure it out? I asked him after crossing lines with UAS-UPRT and Gal-4 driver, how are we going to select the flies? He gave me this: Flies have 4 chromosomes: 2 and 3 are useful for genetics. ...

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by golgicik
Wed Oct 30, 2013 8:46 pm
Forum: Genetics
Topic: Need an help about Drosophila genetics
Replies: 5
Views: 2680

Year 11 Meiosis helpp!!!

Without crossing over, though, you are right - there are duplicate pairs.

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by Darby
Thu Oct 24, 2013 7:26 pm
Forum: Human Biology
Topic: Year 11 Meiosis helpp!!!
Replies: 3
Views: 2955


... background can perhaps put my mind to rest with this question. It says Crossing-over involves the exchange of genetic information between which of the following: sex chromosomes, ...

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by myst
Sat Aug 24, 2013 3:12 pm
Forum: Genetics
Topic: Crossing-over
Replies: 0
Views: 1949
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