crossing over

[elz787]

so on this subject test it says crossing over takes place during prophase I, but then during metaphase I homologous recombination occurs so is it both? or....?

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[mochafreak]

so on this subject test it says crossing over takes place during prophase I, but then during metaphase I homologous recombination occurs so is it both? or....?

I thought it was prophase I...

 

[ndgurl]

Crossing over occurs during prophase I. A synapotnemal complex complex forms joining the homologous chromosomes during synapsis, (when the chromosomes "come to lie lengthwise side by side." ) During late prophase the chromosomes are held together only at regions called "chiasmata," according to my bio book. Each chiasma originates at a crossing-over site. This is also genetic recomibination- "genetic recombination" refers to the new combinations of genes produced from crossing over. I don't know why it says that recombination occurs during metaphase I, as far as I know that is incorrect.