Multiple Choice
A crossover in meiosis is an exchange of genetic material between:
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4. Genetic Mapping and Linkage
Crossing Over and Recombinants
Multiple Choice
Crossing over between homologous chromosomes (genetic recombination) occurs during which phase of meiosis?
A
Prophase II, as the second meiotic spindle forms
B
Anaphase I, when homologous chromosomes separate to opposite poles
C
Metaphase I, when homologous pairs align at the metaphase plate
D
Prophase I (specifically during pachytene, after synapsis has formed)
Verified step by step guidance1
Recall the stages of meiosis, which include Prophase I, Metaphase I, Anaphase I, Prophase II, Metaphase II, Anaphase II, and Telophase II.
Understand that crossing over, or genetic recombination, involves the exchange of genetic material between homologous chromosomes, increasing genetic diversity.
Identify that crossing over occurs during Prophase I, specifically in the pachytene stage, after homologous chromosomes have paired up in a process called synapsis.
Note that during Metaphase I, homologous pairs align at the metaphase plate but crossing over has already occurred by this point.
Recognize that Prophase II and Anaphase I are not stages where crossing over happens; Prophase II involves the second meiotic division, and Anaphase I involves separation of homologous chromosomes.
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